Gu Kailai is facing murder charges in the death of British businessman Neil Haywood last year.
The date is a sign the case is advancing before China's once-a-decade political transition later this year.
The lawyers close to the case spoke to AP on Friday on condition of anonymity because Chinese authorities would likely sanction anyone who discloses details about the tightly controlled case.
Gu Kailai and a family aide — Zhang Xiaojun — have been accused of murdering British businessman Neil Heywood, a close associate of the Bo family. The official Xinhua News Agency says Gu had a falling out with Heywood over money and worried that her son's safety was threatened.
The murder case is at the center of a political scandal that has highlighted factions in the Chinese leadership ahead of the power handover to a younger generation of leaders. Bo was once considered a strong contender for a seat on the all-powerful, nine-member Politburo Standing Committee.
Heywood's death was initially ruled accidental, but murder suspicions surfaced after the police chief who served under Bo, then the party chief in Chongqing city, made a surprise visit to in February a U.S. consulate, where he apparently divulged information linking Gu's involvement to Heywood's death
Bo was sacked from his position in March. He is under party investigation for unspecified discipline violations. No formal charges have been brought against Bo.