The salt content in saline alkali soil is high，which can inhibit the growth of plants or directly cause harm.The safe use of saline alkali soil is of great significance to ensure food security.In order to explore the change characteristics of soil properties and cadmium forms in saline alkali soil affected by chemical fertilizer reduction and application of different organic fertilizers，the experiment was conducted on the basis of 20% reduction in chemical fertilizer application.Four fertilization treatments were set up，including 30000 kg/hm² (AM) of manure，600 kg/hm² (BF) of bio-organic fertilizer，30000 kg/hm² of manure，600 kg/hm² (AM+BF) of bio-organic fertilizer and normal application amount (CK) of chemical fertilizer，to study the effects of different organic fertilizer application on soil properties，cadmium content and forms.The results showed that in 2020，the soil cadmium content in BF treatment soil was 16.99% lower than that in CK；In 2021，compared with CK，the soil cadmium content in BF and AM treatments decreased by 14.06% and 10.16%，respectively，with significant differences.In 2020，compared with CK，the soil available cadmium content in BF，AM and AM+BF treatments decreased by 67.44%，34.88% and 60.47%，respectively；In 2021，compared with CK，the soil available cadmium content of BF，AM and AM+BF treatments decreased by 66.67%，27.27% and 51.52%，respectively，with significant difference.Compared with CK，the distribution proportion of cadmium forms in soil was significantly affected by the combination of organic fertilizer，and the exchangeable cadmium decreased by 19.34%～75.69%；organic bound cadmium increased by 45.78%～135.22%；soil pH increased by 1.06%～5.81%；cation exchange capacity increased by 5.29%～29.11%；organic matter content increased by 4.35%～30.14%；soil bulk density decreased by 0.76%～9.09%；catalase activity increased by 7.84%～56.02%；urease activity increased by 14.67%～29.07%；alkaline phosphatase activity increased by 16.54%～40.09%；microbial biomass carbon increased by 8.02%～25.09%，and microbial biomass nitrogen increased by 12.28%～33.12%.To sum up，under saline alkali soil conditions，combined application of organic fertilizer can improve soil physical and chemical properties and biological characteristics，promote the transformation of soil exchangeable cadmium to organically bound cadmium，and achieve the goal of reducing soil available cadmium.