Peanut and foxtail millet intercropping can produce a better production increase and synergy, but there is not any research report on the photosynthetic response characteristics of the intercropping system. In this test, a research was conducted on the variation characteristics of leaf photosynthetic response and chlorophyll fluorescence parameters under the intercropping conditions of peanut and foxtail millet. The increase in Fo (dark level fluorescence) of intercropping foxtail millet leaves can reduce the reversible inactivation of hard light on foxtail millet leaves; increase in Fm (maximum fluorescence) and Fv/Fm (maximum quantum yield of photosystem II) of intercropping peanut can improve conversion efficiency of the PS II (photosystem II) original light energy of peanut. Meanwhile, dark respiration rate and light compensation point of crops in the intercropping system decreased and the apparent quantum efficiency and light saturation point increased, which can show that the peanut and foxtail millet intercropping can improve the light energy utilization efficiency of them.