To explore the effects of rice-crayfish co-culture system on the contents of heavy metals in paddy soil and rice，field experiments were carried out under different soil backgrounds in Jingmen city and Xishui county of Hubei Province，with Xiangwanxian 12，Huanghuazhan and Yuzhenxiang as experimental materials under rice monoculture as control. The results showed that under the background of weak alkaline soil，the contents of Cr，As，Cd，Pb，and Hg in paddy soil decreased，and the contents of Cd and Pb in roots，stems，spikes，and brown rice decreased. Under the background of weak acid soil，the contents of Cr，As，Cd，Pb and Hg in paddy soil increased，the contents of Cd and Pb in rice roots increased，the contents of Cd in stems，leaves and spikes of rice increased，while the contents of Pb in stems，leaves，and spikes of rice decreased，and the contents of Cd，Pb in brown rice decreased. The results showed that the effects of rice-crayfish co-culture system on the contents of heavy metals in paddy soil and rice under different pH soil backgrounds are inconsistent，but rice-crayfish co-culture system can significantly reduce the contents of Cd and Pb in brown rice.