The study aimed to explore the safe utilization technology of modified biochar in cadmium(Cd)contaminated farmland and realize the safe production of agricultural products. Corn stover biochar was modified with phosphoric acid as the modifier and a pot experiment was conducted with seven treatments，namely，no biochar or modified biochar applied(CK)，20 g/kg biochar application(T1)，50 g/kg biochar application(T2)，100 g/kg biochar application(T3)，20 g/kg modified biochar application(T4)，50 g/kg modified biochar application(T5)，and 100 g/kg modified biochar application(T6)to study the effect of phosphoric acid-modified biochar on Cd uptake and accumulation in Chinese cabbage (Brassica campestris L.)under Cd-contaminated soil. The results showed that the application of biochar and modified biochar significantly increased soil pH and organic matter content. Among them，biochar and modified biochar had the most significant enhancement effect at 100 g/kg application rate. Different application rates of biochar and modified biochar significantly reduced the available Cd content in soil and Cd enrichmentcoefficient of cabbage roots，and the reduction effect of modified biochar was better than that of biochar at the same application rate. Different application rates of biochar and modified biochar significantly reduced the Cd content in the edible part of cabbage，the enrichment coefficient of Cd in the edible part and the transfer coefficient，among which the application rate of 100 g/kg of modified biochar had the most significant effect on the reduction of the enrichment coefficient of Cd and the transfer coefficient of Cd in the edible part of cabbage. They were significantly reduced by 80.00% and 70.20%，respectively，compared with CK. In conclusion，when the application rate of modified biochar was 100 g/kg，it had the best effect on reducing the Cd enrichment coefficient in the root part，Cd enrichment coefficient in the edible part and the transfer coefficient of Chinese cabbage. The application of biochar and modified biochar could effectively remediate the Cd-contaminated cabbage soil and block the transfer of Cd enrichment and absorption in cabbage，in which the effect of modified biochar treatment was better than that of biochar treatment. The results of the study could provide theoretical basis for the safe production of vegetables in heavy metal polluted farmland and promote the recycling of resources and environment.