Jiang, 58, had been head of the Chinese Cabinet's State-owned Assets Supervision and Administration Commission and deputy secretary of its committee of the Communist Party.
Xinhua, the official state news agency, said the senior economist "has been removed from office, suspected of serious disciplinary violations," a phrase referring to corruption. No details were provided.
Members of SASAC's party committee strongly supported the decision, the report said.
"The decision represents the fundamental requirements of the party to be strict with its members and demonstrates the party's steadfast determination to fight corruption," a statement said.
Jiang is the latest high-level Chinese official to face a corruption investigation under new President Xi Jinping's leadership, which has vowed to crack down on official corruption, publicly recognized as a serious problem threatening the country.
The Jiang firing follows last week's highly publicized trial of Bo Xilai, a disgraced Communist Party official, on charges of bribery, abuse of power and embezzlement. Bo, a rising star in the party before his fall last year, has denied all charges against him in court and a ruling is awaited.
Jiang, who had held his job since March, is the first chairman of the commission to be investigated since it was established a decade ago. Jiang also had been chairman of the China National Petroleum Corp., the country's oil and gas producer.
China Daily, quoting a source, earlier reported Jiang's investigation is related to alleged graft when he was head of the company. In August, four senior managers of the CNPC were investigated and the company fired them.
Also last month, it was announced a former vice chairman of the National Development and Reform Commission was expelled from the party and will be further investigated by judicial authorities.
In July, former Railways Minister Liu Zhijun was given a suspended death penalty for bribery and abuse of power, making him the highest-ranking official sentenced for those types of offenses since the new leaders took office in March.
At the Communist Party annual Congress last November, Xi's predecessor, Hu Jintao, speaking about corruption, warned, "If we fail to handle this issue well, it could prove fatal to the party, and even cause the collapse of the party and the fall of the state."