This paper analyses the necessity for petroleum enterprise to carry out target cost management of all staff from four aspects including undefined responsibility main body of petroleum enterprise cost management , unscientific decomposition of target, unclosed loop of process control and insufficient incentives & constraints; and also takes Zhongyuan Oilfield (ZPEB) which is one of the subsidiary giant oil companies of SINOPEC as an example to explore and practise on the target cost management of all staff , regarding “4 systems” of responsibility, target, process control and incentives & constraints of target cost management.