This study investigates the degradation of petroleum hydrocarbon in contaminated soil using activated persulfate (PS) with ultrasound (US) and US/Fe. Various controlling factors including different PS dosage, ultrasonic power, pH, soil water ratio and soil particle size were considered. It was found that petroleum hydrocarbon degradation efficiency achieved up to 56.41% and 82.23% in US/PS and US/Fe/PS system, respectively. Based on the experimental results, the reaction rate of US/Fe/PS system was faster than US/PS system and the degradation efficiency enhanced significantly with the increasing ultrasonic power. Changing initial solution pH influenced the petroleum hydrocarbon reaction rate and the best performance would be achieved at pH of 5. The present work identified the main components of petroleum hydrocarbon pollutants in shale gas sites. The mechanism of petroleum hydrocarbon degradation on US/Fe/PS system were analyzed.