President Xi Jinping cracked down on corruption soon after becoming head of the ruling Communist Party in late 2012, seeking to win back public confidence in the face of a seemingly endless stream of scandals.
The party warned that its own officials were often complicit in cover-ups.
The official Xinhua news agency said the four graft-busters, who worked for the party's Central Commission for Discipline Inspection, had received punishments ranging from dismissal to criminal prosecution.
In the most serious case, Wu Qiang, from southern Jiangxi province, was expelled from the party and handed over for prosecution for killing a pedestrian while driving drnk, and then fleeing the scene, Xinhua said.
Wu Jimian, from central Hubei province was prosecuted for striking and killing a hotel worker while driving a police car after leaving a banquet, the report said.
Shen Wanhao, from northern Hebei province, was sacked after he beat up another corruption fighter at an official banquet, Xinhua added.
A fourth official, Ren Jiangang, from northern Shanxi province, received a party warning for holding banquets to commemorate his father's death, the report said.