Abstract: The paper aims to build a rapid test method of soil moisture content, which would be suitable for application in the field and the laboratory. The soil moisture content was detected by spectrophotometry, the detection process was simple and could be controlled in 5 min for one sample. The results showed that the maximum absorption wavelength of the solution was 660 nm, the concentration and volume of chromogenic agent were 3.5 g/L and 10 mL. The error of the testing result would be 1.4% or less when the concentration of Cl- was 0.45 mg/L or less (the equivalent of Cl- was 0.45 mg/kg in the soil). Therefore, the test method of soil moisture content was suitable for most agrotypes, because the average concentration of Cl- was 0.1 mg/kg. The absolute error of the rapid detection result was 3% or less comparing with the oven drying method, and it was hardly affected by agrotype and chemical compositions. It was a rapid and convenient test method which had promotion value and application advantages.