Abstract: Chlorophyll content is an important indirect agronomic parameter judging corn nutrition status, which has significant meaning for crop growth monitoring. The author measured the canopy spectral reflectance and chlorophyll relative content of summer corn in key growth period by using ASD portable spectrometer and SPAD-502 chlorophyll meter. Correlation analysis of the 3 vegetation indexes and chlorophyll relative content were also conducted. The author established an estimation model based on the normalized difference vegetation index (NDVI), the ratio of vegetation index (RVI) and difference vegetation index (DVI) of chlorophyll and selected a best fitting model from accuracy test. The results showed that the RMSE and RE of jointing stage RVI, heading stage and filling stage NDVI and dough stage DVI were the lowest. The RMSE were 5.688, 5.323, 2.751 and 4.111, respectively, and RE were 9.84%, 8.56%, 3.75% and 7.15%, respectively, so they were the best models of each period. Therefore, the optimal models of the 3 vegetation indexes (NDVI, RVI and DVI) were achieved in different growth stages. It has guiding significance for the cultivation of summer corn and field management.