Soil heavy metal pollution has become one of the main problems threatening the soil ecological environment and rice food safety in southern China. Planting and turning Chinese milk vetch in winter can fertilize the soil and reduce the bioavailability of heavy metals in the soil. Biochar is widely used in the remediation of heavy metal soil pollution due to its well-developed pore structure and abundant surface functional groups. However，the effect of Chinese milk vetch returning to field and biochar application on soil heavy metal compound pollution is still unclear. This article focused on the soil contaminated with heavy metals cadmium(Cd)and copper(Cu)in the Cu mining area of Daye city. Through pot experiments of rice，the effects of applying 22500 and 30000 kg/hm² of Chinese milk vetch(MV1，MV2)alone and 5 g/kg of biochar(B)，as well as the combination of Chinese milk vetch and biochar(MV1B，MV2B)，on soil properties，soil available Cd and Cu contents，and the absorption and transport of Cd and Cu by rice were studied. The results showed that compared with CK，the treatments of biochar alone and Chinese milk vetch and biochar(B，MV1B，MV2B)increased the yield by 15.1%，19.5% and 20.9%，respectively. The combined application of Chinese milk vetch and biochar significantly increased the soil pH by 0.15-0.26，and the occurrence forms of Cd and Cu in the soil changed from the oxide-bound state and residue state with low activity to the organic binding state and exchange state with high activity. The application of Chinese milk vetch could significantly reduce the transport coefficient of Cd and Cu from rice roots to stems and leaves，reduce the enrichment coefficient of shoots，promote the formation of root surface iron film，increase the content of Cd in root surface iron film，and reduce the transport of Cd and Cu to rice shoots. Compared with MV2 treatment，B treatment increased soil organic matter by 9.2%，and increased the contents of Cd and Cu in brown rice by 12.90% and 64.89%，respectively. Compared with MV2 treatment，the MV2B treatment increased the soil organic matter by 10.28%，and decreased the contents of Cd and Cu in brown rice by 48.39% and 53.55%，respectively. Compared with other treatments，the application of high returning amount of Chinese milk vetch combined with biochar(MV2B)had a higher yield increase and a lower effect on the contents of Cd and Cu in brown rice.