This article focuses on the problems of fuel consumption and driving smoothness existing in the engine starting process of oil-electric parallel hybrid vehicles. It conducts a comparative analysis of the performance of traditional starter starting and motor-driven starting，and conducts real vehicle tests. Under the same working conditions with engine water temperature around 70℃，collect the instantaneous fuel injection volume and vehicle body shaking data of different starting methods to quantitatively evaluate the fuel-saving effect and driving experience. The results show that when the motor drives the start-up，controlling the rotational speed at 700r/min can achieve the lowest instantaneous fuel consumption（3.05L/h），and there is no obvious shaking of the vehicle body. It is the optimal start-up control strategy.