Bo, the former Communist Party chief in Chongqing and one of the most influential men in China, is accused of bribery, corruption and abusing his office by using his position to cover up the actions of his wife, Gu Kailai, who has been convicted in the murder of British businessman Neil Heywood, the BBC reported.
Prosecutors say Bo took bribes of about $3.5 million from businessmen Tang Xiaolin and Xu Ming and embezzled $800,000 which had been earmarked for a Dalian city construction project.
Witness Wang Zhenggang said he overheard Bo on the phone with his wife in which he explicitly said he would funnel money to the family.
But Bo said: "Is this in line with the way an embezzler would think? ... It is not even what the most stupid corruption offender would do."
"On the matter of abuse of office, I made mistakes, this reflected badly on the image of the party and the state. I feel sorry for that," Bo told the Jinan court Saturday. "However I do think the charges against me exaggerated my role in these incidents."
Bo said he discussed the accusations against his wife with her and that she told him that she was being framed for murder. Bo also allegedly slapped his deputy, Wang Lijun, in the face when he accused Gu of being responsible for Heywood's death.
"I never meant to ... protect Gu. I didn't mean to force Wang Lijun away," Mr Bo said.
Wang also testified at the trial Saturday, China's state-run Xinhua news agency reported.
Wang was sentenced to 15 years in prison in September for selfish ends, defection, abuse of power and bribe-taking,