BEIJING, Sept 5 (Reuters) - A senior Chinese official was executed on Wednesday for ordering the murder of his mistress in a car bomb attack, state media reported.

Duan Yihe, 61, former head of the municipal council in Jinan, capital of the eastern province of Shandong, was put to death less than two months after Liu Haiping, 31, died in a powerful explosion in her car, the Xinhua news agency said.

Local policeman Chen Zhi, married to Duan's niece, was also executed after being convicted of actually planting the explosives under Liu's car, Xinhua said.

The owner of a car repair shop who had helped with the crime was jailed for life, the news agency added.

Chinese Web sites carried gruesome pictures of the crime scene, and news that a senior Communist Party official was responsible caused widespread scandal.

Duan began his relationship with Liu in 2000, buying a house for the divorced former waitress and arranging jobs for many of her relatives, media reports said.

He later became irritated at Liu's continuing demands for money and insistence that he get a divorce and marry her, the reports said. She eventually threatened to report him for corruption.

Duan was arrested a week after Liu's murder on July 9. As well as the murder charge, Duan was tried and found guilty of taking bribes and asking for money with a total value of 1.69 million yuan (more than $220,000).

Corruption has become rampant among Communist Party officials since China launched market-oriented reforms in the late 1970s, fuelling mounting public discontent.

Zheng Xiaoyu, former head of the State Food and Drug Administration, was executed in July for taking bribes from drug makers. Fake or toxic drugs killed dozens of Chinese on his watch.