Abstract: In order to study bioremediation of petroleum contaminated soil,petroleum contaminated soils were collected from the Zhongyuan Oil Field and microorganisms that degradate petroleum were screened from the soil.Then,samples of contamination-free Fluvo-aquic soil were collected from the same area and mixed with 15 g·kg^-1 petroleum for pot experiment to study effects of the microorganisims and plants on remediation of the petroleum contaminated soil.The experiment was designed to have three treatments,(1)adding microorganisms,(2)growing plants,and(3)growing plants plus adding microorganisms.Results show that in Treatment 1,the degradation rate of petroleum was 67.0% after 120 days;in Treatment 2,it was 38.23%,36.57%,40.67% and 38.67%,respectively,with sunflower,cotton,bermuda grass,and sudan grass;and in Treatment 3(cotton + microorganisms)it reached as high as 85.67%.