Using the Tessier A method, the three chemical forms of selected heavy metals were determined to investigate the speciation and bioavailability of selected heavy metals in arid oasis soil-plant system. The findings showed that the chemical form contents of metal Cd, Zn, and Ni mainly existed in residual fraction in untreated soils, while in treated oasis soils those about the exotic metal Cd, Zn, and Ni were found predominantly in carbonate forms to element Cd, and Fe-Mn oxides bound forms to metal Zn and Ni. The passivation of these heavy metals in oasis soil fluctuated smoothly and the activity order of selected heavy metals was Cd＞Ni＞Zn. According to the results of regression analysis, it was found that CAB-Zn and FMO-Zn made the significant contribution to the accumulation of metal Zn in the tuber and stem of Daucus Carota, and FMO-Ni to the accumulation of metal Ni in both tissues.