Abstract: Our objective was to explore the mechanism of spectral reflectance response to leaf photosynthetic pigment seasonal dynamic of Quercus aliena var. acuteserrata under throughfall elimination. We simulated rainfall decline through throughfall elimination (TFE) treatment in the experiment plots of Baotianman Natural Reserve in Henan, measured leaf pigment content and its spectral reflectance during growing season in both TFE and control plots. We analyzed seasonal changes of photosynthetic pigments and changes of pigments induced by TFE and their spectral reflectance responses. The results showed that all photosynthetic pigments content and pigment-ratios exhibited clear seasonal patterns. Leaf photosynthetic pigments content and ratio had differences between TFE plot and control plot during the whole growing season, and significant difference was found in chlorophyll b (Chl b) indicating that Chl b had higher sensitivity than other pigments. Carotenoids (Car) content showed minor difference compared with other pigments, indicating that Car had less sensitivity to TFE. The spectral reflectance of 550 nm was found to be the waveband most sensitive to seasonal changes of pigments, so we formulated the sample ratio index (SR_750,550) based on it. The strong positive relationships between SR_750,550 and Chl a, Chl b, Chl and Car contents were found with high significant level. Similarly, significant negative relationships were also been found between photochemical reflectance index (PRI) and Car/Chl. The spectral reflectance of 550 nm was most sensitive to changes of pigments induced by TFE. SR_750,550 was sensitive to changes of leaf Chl a, Chl b and Chl content induced by TFE (P＜0.01), but not to change of Chl a/b. PRI was sensitive to change of leaf Car/Chl induced by TFE (P＜0.01).