According to the investigational data of petroleum hydrocarbon content in Wenzhou coastal waters from 2006 to 2009, the distributional character and pollution degree of petroleum hydrocarbon of the investigational sea area were studied with single factor index method. The results showed that the range of petroleum hydrocarbon content in water was from non-detected to 0.085 mg/L, and the mean was 0.018 mg/L. Petroleum hydrocarbon content met the first class sea water quality standard (≤0.05 mg/L) in almost all sampling stations except one station in 2008 and 2009, respectively.