Abstract: Based on rapid determination technology research of soil organic carbon content in scene, an analysis method of visible and near infrared reflectance spectroscopy for soil samples was proposed. The 400 ～ 1 100 nm band spectrum was pretreated by S-G smoothing and with first order differential filtering，and the prediction model of soil organic carbon was established by partial least squares regression analysis（PLSR）. The results showed when the ratio of the sample number of the modeling group and the sample number of the predicted group was 52∶53（about 1∶1），the determining coefficient was R² =0. 98, and the standard deviation of the root mean square error of calibration was RMSEC = 0. 25. These results indicate when the ratio of the sample number in the modeling group and in the prediction group is set to 1∶1，it is the best condition to establish the prediction model based on PLSR for soil organic carbon.

Key words: soil organic carbon, visible and near infrared spectroscopy technology, partial least squares regression