The effects of different types of shell powder on different forms of cadmium in soil were investigated through indoor culture. Three proportions of natural scallop shell powder and ascarid shell powder were applied to the soil after the culture. The soil pH and cadmium forms were measured on the 1st, 5th, 15th, 30th and 50th days after the application of shell powder, respectively. The results showed that the addition of aragonite and calcite shell powder contributed to the increase of soil pH. After adding the two kinds of shell powder, the soil pH increased with the increasing of shell powder addition ratio. The pH value of soil treated with different kinds of shell powder was not different, and the difference in soil pH value was the most obvious among different addition ratios after 50 days. During the whole cultivation process, with the increasing of the culture days, shell powders could reduce the exchangeable cadmium content in the cadmium-contaminated soil, while the contents of carbonate-bound cadmium, iron-manganese oxides, organic-bound cadmium and residual cadmium increased gradually as a whole. Among them, the applying the aragonite shell powder as a passivating agent was more effective than the calcite type. As the proportion of shell powder increased, the exchangeable cadmium changed to other cadmium speciation was more. After 50 days of culture, the contents of available cadmium in soils treated with shell powder were significantly lower than that of CK. When the addition ratio of shell powder was 5%, the bioavailable cadmium accounted for the lowest proportion of total cadmium. The results showed that aragonite shell powder had better effect of reducing soil available cadmium activity than that of calcite shell powder.