||Perennial ryegrass (Lolium perenne L.) was commonly used for urban green planting such as lawns, which was not only affected by sunlight, but also by light pollution caused by night artificial lighting. In order to see the ryegrass growth, physiological characters and chlorophyll fluorescence response to light pollution and provide the suitable lighting time, 6 different artificial lighting times (24/0 h, 22/2 h, 20/4 h, 18/6 h, 16/8 h and 14/10 h) were conducted in growth chambers. There were significant systematic differences in perennial ryegrass growth characters in seed germination rate, leaf length (LL) and leaf weight (LW) (F = 47.99, 28.34, 13.47, respectively; P < 0.01) while under 16/8h lighting time treatment which had the highest values and the increasing lighting time decreased the growth. It had the best effect under 16/8h lighting time treatment on leaf physiological reactions and also significant. The maximum curvature point temperature (TCC) was significant different (F = 28.08, P < 0.01). The relative variable fluorescence differences at 2 ms (VJ) was increased with the lighting time increased (F = 20.25, P < 0.01). The results of reaction center (RC) of PSII under 6 lighting times also had significant differences. For the result of the yield and efficiency of electron transport chain (ETC), Fv/Fm (φP0), ψ0 and φE0 showed the significantly increased trend with the lighting time decreased while the φD0 was decreased. The shape of the OJIP curves was sensitive to the lighting times which showed that with the increasing lighting times the chlorophyll fluorescence intensity changed and shifted the fluorescence curve lower. Leaf light-response curves (LC) were also significant under 6 lighting times. Significant positive correlations were found between leaf physiological characters (SP, SC, Chl a, Chl b, Chl a + b, WP and TCC) and J-I-P test chlorophyll fluorescence parameters (PIABS, ABS/RC and TR0/RC) except ET0/RC while the correlation with DI0/RC was significant negative. There were significant positive correlations between leaf physiological characters (SP, SC, Chl a, Chl b, Chl a + b, WP and TCC) and φP0, φE0, ψ0 while the relationships with φD0 were significantly negative. Nighttime artificial lighting acted as a depressor of the fitness of photosynthesis and growth characters, via the changing of the photosynthetic apparatus.