Abstract: The study analyzed the horizontal distribution and seasonal variation of petroleum hydrocarbons, based on the data collected from the investigation of concentrations of petroleum hydrocarbons in surface water of Laizhou bay from May 2011 to Nov. 2013. The results showed that the oil content in surface water of Laizhou bay were 0.00900~0.101mg/L, 0.00875~0.0879mg/L and 0.0118~0.0687mg/L.The overall interannual changes were not significant, but presented apparent seasonal variation. The oil concentration in summer was higher than spring in 2011,the average content had a trend of spring > summer > autumn. According to the spatial distribution, the values in coastal area were higher than the center and mouth of Laizhou bay. And the higher values appeared at Xiaoqing River estuary and Huanghe estuary.