Through the indoor simulated culture experiment, the effects of iron-manganese bimetal (FMBO) on the passivation and ecological effects of three As and heavy metal composite contaminated soils were studied. The results showed that the effective content of As and heavy metals in the contaminated soil decreased gradually with the increase of FMBO in the range of 0%~5%. Compared with the control, under the condition of 5% addition, As, Pb, The effective concentration of Cd, Zn and Cu decreased by 93.7%~100%, 30.8%~57.8%, 81.3%~95.0%, 66.7%~95.3%, 55.8%~100%, respectively. According to the results of seed germination experiment, when the amount of FMBO added was 2.5%, FMBO could attenuate the growth and development of plants in contaminated soil; when the addition amount was 2.5%, the growth of wheat seeds cultured in contaminated soil leaching solution Optimal, seed germination rate, root length and plant height can reach 86%~92%, 7.25~9.09 cm and 8.62~9.91 cm, respectively, and when the amount of FMBO added reaches 5%, it inhibits seed germination and growth. . According to the results of soil microbial diversity analysis, the FMBO material reduced the Shannon-Werner diversity index of soil microbes and changed the community composition. Therefore, before the passivation and repair of heavy metal contaminated soil, it is necessary to consider both the passivation effect and the ecological effect, and determine the optimal addition amount of the repair material.