The former energy tycoon appeared in court on Monday as his trial into alleged corruption began.
The ex-oil executive was charged last month with taking advantage of his position to seek benefits for others, and of extorting and receiving large amounts of bribes.
Jiang is being tried at Hanjiang Intermediate People’s Court in Hubei province, Reuters reported.
The news wire later on Monday reported that Jiang had confessed to his indiscretions.
"The facts of my crimes are clear, the evidence is true and conclusive," Jiang was quoted as saying in a court statement referenced by Reuters.
"I admit my crimes and am penitent," he is said to have continued.
The trial of the man who also briefly ran the state asset regulator before being sacked is expected to take a couple of days.
Chinese authorities have arrested and charged a number of senior oil industry executive and former executives, as well as other businessmen and politicians, as it looks to flush out corruption in industry and politics.