Little study carried out the soil washing experiments using pot experiments to simulate in-situ soil washing operation, particularly for the alkaline soil. This study explored the effect of multiple washing operation using pot experiments on the removal efficiencies of heavy metals from the alkaline farmland soil and the reuse strategy of the washed soil for safe agricultural production. The results showed that the removal efficiencies of Cd, Pb, Cu and Zn after the seven times washing with the mixed chelator (EDTA, GLDA and citric acid) were 41.1%, 47.1%, 14.7% and 26.5%, respectively, which were close to those from the results of EDTA treatment. For the alkaline soil studied, the 2nd washing with the mixed chelator most effectively removed heavy metals owing to the activation of heavy metals after the first washing operation. The mixed chelator more effectively increased the proportion of stable speciation of heavy metals and maintained soil nutrients such as nitrogen content in soil than EDTA did, indicating the little disturbance of alkaline soil quality after being washed by the mixed chelator. After application of amendment into the washed soil, there was no visible difference in biomass weight of crops from the soil washed with different agents, indicating that the inhibitory effect of both washing agents on the plant growth was effectively alleviated. The Cd and Pb in Z. may were below the threshold of Hygienical Standard for Feeds of China (GB 13078 − 2017) (1 and 30 mg·kg− 1). Moreover, after three times of cropping, the concentrations of available heavy metals in the soil washed with the mixed chelator were lower than those in the washed soil with EDTA, indicating the value and potential of agricultural reuse of alkaline farmland soil being washed with the mixed chelator here.