Abstract: Collecting 10 kinds of alfalfa samples from national technical system of grass industry in Suihua general field, we measured some indexes of alfalfa with near-infrared-reflectance Spectroscopy (NIRS) and conventional chemical assay (CCA). The crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), fat (FAT), ash (ASH) and dry matter (DM) were detected. Compared with paired T value analysis by SPSS, the results show that X ± S are approximate between two methods, |t|<0.05, P>0.05. Calculating the standard deviation (SD) and the relative standard deviation (RSD) respectively, we find that the value of NIRS is less than CCA. The results also show that NIRS can be used as a new detection method, based on the comparison with CCA.