In this paper, the key analytical conditions were discussed which affected the determination results of the cationic exchange capacity in soil by ammonium acetate exchangevolumetricy method. The test results showed that the optimal analytical conditions were: the size of the soil sample was 20 meshes by grinding, the solidliquid ratio of soil sample and ammonium acetate solution was 2g∶50 mL, the oscillation frequency was 240 r/min and the oscillation time was 4 min, the amount of ethanol used as an ammonium ion eluent was 150 mL which was divided into an average of three times, the distilled liquid volume was 120 mL which was distilled by steam. By the methods validation, the detection limit was 1.0 cmol/kg, the quantitative limit was 4.0 cmol/kg and the relative standard deviation was from 2.4% to 4.6% (n= 6) in representative samples which the pH was ranged from 5.69 to 8.13, at the same time, the results of soil standard samples are consistent with the standard values. Therefore, the method had excellent applicability, and can meet the quality requirement of national soil environmental monitoring and farmland investigation. 