Micro-ecological response of three types of soils in Shandong Province to incorporation of oily sludge were studied.Soil microbial population and enzyme activity were used as indice to evaluate effects of petroleum-containing soil on soil ecosystem. Results show that the effects of petroleum pollution on soil microbial flora and soil enzyme activity varied with the type of soil. It was found that brown soil was the strongest in self-restoration capability and the least affected in microbial flora by total petroleum hydrocarbon, suggesting that it can be the first choice for phytoremediation of petroleum-polluted soil. The effect of petroleum hydrocarbon content was the most significant on actinomycete among the three microbial groups in the soil. With soil TPH content set at 500 mg kg^-1, the total count of actinomycete declined by 80%, 85% and 89% in fluvoaquic soil, cinnamon soil and brown soil, respectively. The effect of TPH on the fungi population was much less in cinnamon soil and brown soil than in fluvo-aquic soil. The variation of Amylase and unease with the TPH content in the three types of soils indicated that amylase in cinnamon soil and fluvo-aquic soil was sensitive to TPH content and could be used as a biological index in determination of petroleum contamination of soils.