Abstract: In order to explore the dynamic balance of heavy metals in the soil-crop system and the sensitive period of heavy metal uptake, field plot test was conducted with micro-polluted water of different concentrations of Cd. The results showed that, compared with the treatment of clear water, the Cd content of 0-10 cm soil layer significantly increased under micro-polluted water irrigation treatment. The take away Cd content of the aboveground part was far less than the irrigation input Cd content, which affected the balance of the soil Cd. The filling stage was the sensitive period of winter wheat and not suitable for micro-polluted water irrigation. The winter wheat grain plumpness was reduced with micro-polluted water irrigation, and the yield of the winter wheat was significantly reduced. In conclusion, Cd micro-polluted water irrigation could influence Cd balance in soil-crop system, especially in the filling period.