Abstract: The aim was to detect the content of soil sucrase precisely. The effect of different wavelengths, the amount of chromogenic agent and toluene, heating time and the stable time of color on the content of soil sucrase detected by 3,5-2 dinitrosalicylic acid (DNS) method was analyzed. The results showed that when the wavelength was 510 nm, the amount of reagent was 1.5 mL, the amount of toluene was 0.1 mL, the time of water bath was 5 min, storage time of the solution to be determined was less than 4 h, the stable time of color was between 0.5-2 h, the standard curve in the range of 0.25-2 mg had good linear relation (R2=0.9991), the coefficient of variation (CV) was less than 9% , the recoveries were in the range of 96%- 109% , and the precision and accuracy of the test results were relatively high. The above method was safe, economical and efficient, and suitable for batch determination of soil sucrase.