Abstract: Ceramisite, activated carbon, peat etc. were screened for remediation of petroleum contaminated groundwater. The effective, economical and safe peat was selected as the PRB reactive media to analyze the effects of hydrochemistry factors such as Mn²⁺, Fe²⁺, Fe³⁺, NO₃^-, SO₄^2- on the purification efficiency. Experiments results indicated that every ion had different influence on purification efficiency. Purification efficiency had no effect with NO₃^-. It could be promoted by SO₄^2- except that the concentration of SO₄^2- was 200mg/L. It was promoted with the increment of the concentration of Mn²⁺and Fe²⁺. Finally, microstructure of peat before and after adsorption was compared. The results showed that peat had porous structure and regular arrangement. Petroleum hydrocarbons were found in the most pores of peat after adsorption. This research provided key reactive media for the application and promotion of PRB for the insitu remediation of petroleum contaminated groundwater.