Persulfate-based in situ chemical oxidation (PS-ISCO) has been widely used in soil and groundwater remediation. Soil properties have important influences on the decomposition of persulfate and generation of free radicals, but the related studies are rather limited. Therefore, we selected 16 typical soils with different properties in China and studied persulfate decomposition and free radical generation, then further analyzed the effects of soil organic matter, iron and manganese content and particle composition on this process. The results show that soil organic matter, soil amorphous Mn content, and soil sand content are significantly and positively correlated with the decomposition rate of persulfate, while the correlation between the content of different forms of iron and manganese and the persulfate decomposition rate is not significant. The above results indicate that soil organic matter, amorphous Mn, and sand particles may be the key factors affecting the PS-ISCO, which will provide theoretical support for the application of persulfate in soil remediation.