In order to estimate the chlorophyll content and composition of pepper leaves without damage, simply,quickly, accurately and improve the level of crop fine management. In this paper, the absorbance of pepper leaves was calculated by spectral transmittance, the absorption peaks of chlorophyll a and chlorophyll b content in leaves were found at 640 ～ 690 nm by fourth order derivative method（649, 668 and 681 nm）. The detection models of chlorophyll a and chlorophyll b content were established and compared by using multiple linear regression. The model established by absorbance at 649, 668 and 681 nm had the best results in predicting the content of chlorophyll a.the relative error（RE） of the test results was 8.86%, and the determination coefficient（R²） was 0.879. The model established by absorbance at 649 and 681 nm had the best results in predicting chlorophyll b content. The relative error（RE） of the test results was 9.84%, and the determination coefficient（R²） was 0.878.