Abstract: To improve the detection efficiency of the cation exchange capacity in soil, in view of the deficiency of the present standard, this study puts forward a rapid detection method by combining the pretreatment system of cation exchange capacity and Kjeltec Automatic Azotometer. The analytical steps of centrifugal and distillation titration were optimized and improved. On the premise of constant principle, the parameters of the instrument were optimized. The results were as follows: ammonium acetate was stirred for 15 min; ethanol was used to wash the soil for 4 times, and distilled for 5 min. Under the condition, the precision and accuracy of this analysis method were in accordance with the requirements by testing the national soil certified reference materials. Thus the analysis method is simple, efficient, accurate and reproducible. It is suitable for the determination of the cation exchange capacity in large quantities of soil samples.