Abstract: A method for identifying the immuneactivity of iodine ［¹³¹I］aiketuoxi monoclonal antibody injection was developed. The paper reported the method of percentage of living cells. Cell selection, the effect of temperature, time and separation method were studied, and as well as the stability of the product and the coefficient of variation were analysed by the method. The cell line was CEA expression positive LS180 cell, reaction time was 16 h, reaction temperature was 4 ℃, and it used a direct separation method. The variation coefficient of the method was less than 10%. The method has good reproducibility and can be used for analysis the immuneactivity of iodine ［¹³¹I］aiketuoxi monoclonal antibody injection.