Carbonation is an important factor affecting the durability of cement-solidified heavy metal-contaminated soils. In order to explore the influence of carbonation on the strength of solidified contaminated soils, lead-contaminated soils were artificially prepared, and carbonation tests were carried out after cement solidification treatment. The effects of carbonation and compactness on unconfined compressive strength(UCS) of solidified soils were analyzed, and the effects of carbonation on micro mineral morphology and micro pore structure were also analyzed by electron microscope scanning and mercury injection tests. The test results show that UCS of solidified lead-contaminated soils decreases under carbonation, the strength of solidified soils with 15% cement content is reduced by 44%-45%, which is the result of the filling enhancement effect of carbonation reaction products and the weakening of cementation between soil particles. There is a good power function relationship between UCS and porosity of solidified soils, which reveals the influence of filling on strength of solidified soils. Under carbonation, crystalline carbonation reaction product CaCO₃ is observed, the total pore volume of solidified soils decreases, the proportion of gel pores less than 0.01 μm and capillary pores between 0.01 μm and 0.1 μm decreases, and the proportion of capillary pores between 0.1 μm and 10 μm and macro pores greater than 10 μm increases.