The utility model discloses a treating device for petroleum hydrocarbon polluted soil. The treating device comprises a counterbalance foundation block and a pneumatic membrane, wherein a gas tight door is arranged on the pneumatic membrane, a spraying system, an aeration system and a temperature monitoring device are arranged inside the pneumatic membrane, the aeration system and the temperature monitoring device are arranged on the right side of the spraying system, a leachate collecting system comprising a leachate level monitoring device is arranged at the lower end of the inner side of the pneumatic membrane, an impervious layer is arranged at the lower end of the leachate collecting system, both the leachate level monitoring device and the temperature monitoring device are connected with a controller on the outer side of the pneumatic membrane, blowers are arranged on both the left side and the right side of the exterior of the pneumatic membrane, a gas absorption treating device is arranged between the pneumatic membrane and the blower on the right side, an exhaust chimney is arranged on the right side of the blower, the pneumatic membrane comprises a kynar PVDF (Polyvinylidene Fluoride) coating layer, and a fabric layer and a mildew-proof coating layer are arranged on the inner side of the PVDF coating layer in sequence. The treating device provided by the utility model has the benefits as follows: influences caused by the temperature of the system to microbes can be effectively controlled, the activity and the quantity of the microbes are ensured, and the speed and the efficiency in treating the polluted soil can be effectively ensured.