Mickey Mouse will don pin stripes Oct. 1.
The 4 1/2-foot-high symbol of Disney World will become a ''a company mouse'' when Walt Disney Productions opens its $800 million EPCOT Center project on that date.
EPCOT, standing for the Experimental Prototype Community of Tomorrow, will provide a ''permanent World's Fair,'' where eight companies, initially, will sponsor pavilions with such titles as ''Spaceship Earth,'' ''The Universe of Energy,'' and ''The Land.'' According to Disney spokesmen, the pavilions will be a showcase for the ''technologies of the future,'' and will be known as Future World.
In addition, Disney is constructing what it calls World Showcase, which includes eight pavilions from such countries as Britain, France, West Germany, Japan, Canada, and Mexico. Corporations from the host countries will underwrite part of the expense of the pavilions and will be hawking some of their products.
Not surprisingly, the corporate patrons, writing checks for several million dollars, hope their sponsorship will enhance their names in the eyes of the public.
''It's a great showcase for the company, even though we don't have consumer products,'' notes Robin Carlson, a spokesman for Sperry Univac, which is participating in a pavilion called Computer Central. ''We'll have a VIP lounge for meetings and sales pitches.''
Still other companies will use their pavilions for board meetings and company powwows. Exxon, sponsor of the energy pavilion, is considering holding its 1983 annual meeting in the area so that its shareholders can see its exhibit.
Kraft, sponsor of ''The Land,'' says it will hold a meeting of its 2,500 to 3 ,000 retail sales representatives in Orlando in December and give them a tour of the exhibit. The annual meeting may be held in the exhibit in spring 1983, says Kraft vice-president Richard N. Courtice.
The other corporate sponsors are General Motors, General Electric, Eastman Kodak, and American Telephone & Telegraph. Although all the companies have steadfastly refused to disclose the cost of the project, outside sources have indicated the companies have generally paid between $20 million and $40 million for 10-year leases.
Time Inc. had originally agreed to sponsor a polling operation, called Future Choice Theater, but pulled out. Some, like General Motors, with earnings problems, probably wish they weren't involved.
Some observers feel that corporate sponsorship of pavilions exhibiting ''technologies of the future'' could pose some problems. The sponsor of a particular pavilion might not have state-of-the-art technology in its field. And it's doubtful that corporate sponsors would give competitors' technology much play.
But in any case, the expansion of Disney World is expected to have a great impact on the Orlando area. For example, Charles Ridgeway, a Disney spokesman, estimates attendance will increase from 13.5 million annually to 20 million. This will require an additional 15,000 to 20,000 hotel rooms.
EPCOT, which will be next to Disney World, will also expand employment. Disney, already the area's largest employer, with 12,000 to 15,000 workers, will hire 2,000 to 3,000 more to keep its exhibits running smoothly.
Disney also expects the tourists to stay longer on its grounds. Mr. Ridgeway says the company estimates the average length of stay will expand by a full day. Since the typical tourist spends from $16 to $18 a day at Disney, this will obviously bolster Disney's revenues. This is good news locally, since attendance at Disney World has declined for the past four years.
The longer stay, however, could squeeze neighboring theme parks and other attractions trying to garner a few of the tourist dollars once they leave Disney.
''The smaller attractions will probably fall by the wayside,'' comments Hans W. Tews, president of Sun Bank, ''since they can't buy the publicity.''
Dr. Frederick A. Raffa, a professor of economics at the University of Central Florida, agrees: ''Over the short run it's going to hurt the others.''
Not everyone thinks the other theme parks will be hurt, however. George Becker, president of Sea World, a nearby attraction, concedes that EPCOT may cause a shakeout ''somewhere in Florida.'' But, he believes, the tourist may end up spending more time in central Florida and less time elsewhere. Southern Florida, including Miami and the Keys, may become the net loser, one analyst says.
One economist in the area says some of the more isolated theme parks, such as Silver Springs, or lesser known ones such as Stars Hall of Fame, may be hurt the most. One attraction, Laser World in downtown Orlando, has already closed ''for renovation.''
There will be yet another theme park in the area competing for the tourist dollar when MCA Inc., owner of Universal Studios, opens up a $170 million studio and theme park in 1984. The addition of ''Hollywood South,'' says Mayor Bill Frederick, should just about saturate the market for theme parks in the area.
The East Central Florida Regional Planning Council estimates the MCA project could attract 4 million visitors annually, making it the second-biggest attraction in Florida.
EPCOT, whose designers have an eye on the changing demographics of the United States, is designed to appeal to the burgeoning 25-to-44 age group instead of the roller coaster crowd.
Despite the emphasis Disney likes to put on the educational aspect of EPCOT, one company spokesman involved with it notes that ''it's a little bit of education and a ton of entertainment.''