Abstract: To investigate the ecological adaptability of leguminous forage under different shade conditions and seek appropriate shading proportions, the photosynthetic characteristics and chlorophyll fluorescence parameters of three kinds of leguminous forage were determined under three shade conditions (0%, 48%, 70%, 95%). The results of the experiment showed that the light compensation point (LCP) and light saturation point (LSP) of Trifolium repens were at a low level. Medicago sativa and Melilotus suaveolens could maintain low LCP and LSP in the appropriate shade conditions, but they decreased with an increase in shade. The content of chlorophyll a, chlorophyll b and total chlorophyll a+b ratio in leaves decreased with increasing shade and the levels in T. repens were higher than those in the other two f legumes in the same shading treatments. The chlorophyll a/b ratio maximum performance of M. sativa was in the Y3 treatment. The order of leguminous forage for sensitivity to PSⅡinjury was: M. sativa＞M. suaveolens＞T. repens; The ΦPSⅡ and qP of T. repens and M. suaveolens were slightly reduced with shading, while those of T. repens were slightly increased under Y3 treatment conditions, and the M. sativa initially increased but then decreased with an increase of shading.The shading intensity sequence of the three kinds of leguminous forage was: T. repens＞M. suaveolens＞M. sativa. T. repens could still grow well in more than 70% shade, M. suaveolens were grew well under 48% shade, and M. sativa was greatly affected by shade.