The sensor for soil moisture measurement should have broad adaptability, and the soil moisture can be measured by the sensor upon the determination of the relationship between soil moisture and relevant variable. Five typical soils from different geographic locations of China were sampled for soil moisture measurement test with the near infrared sensor designed with 1940nm as measuring wavelength and 1800nm as reference wavelength. The reflectance of those two wavelengths was transformed to relative absorbance depth to minimize the influencing factors. The results indicate there existing strong linear correlation between soil moisture and relative absorption depth for different soils. Independent data sets were used to validate the calibration model, and the root mean square error is less than 6% except for the red soil from southern China. The research shows the adaptability of the sensor for different soils and the calibration steps.