Abstract: Taking yellow heart celery as the test materials, and artificial lighting as the research method, the light quality was set as red light（R）,red light∶blue light=3∶1（3R1B）,red light∶blue light=1∶3（1R3B）,blue light（B）,and white light of control group（W）,the effects of different ratios of red and blue light on the growth of celery seedlings and the electron transfer of photosynthetic system were investigated, in order to screen out suitable treatment of strong seedlings and understand the regulation mechanism of red and blue light on the light system of celery seedlings.The results showed that, compared with the control, treatment R significantly promoted the increase of plant height and leaf area but significantly reduced the stem diameter and root length of celery seedlings, while treatment B,on the contrary, had the smallest plant height and leaf area but the largest root length and stem diameter of celery seedlings.The seedling index of B was the significantly higher than that of other combinations, and the accumulation of total fresh weight and total dry weight of B was the second only to that of R.Phenotypic and biomass differences between 1R3B and 3R1B were not significant.Compared with R and 3R1B,W,B,1R3B were more conducive to the accumulation of photosynthetic pigments.OJIP curve and JIP-test analysis showed that the relative fluorescence intensity of point J treated by R was significantly higher than that of other treatments, and point I was also the largest, indicated that red light inhibited the reduction of Q_A,Q_B and PQ libraries on the PSⅡ receptor side, and inhibited electron transport and PSⅡ activity.Monochromatic blue light treatment was the best treatment of strong seedlings, and had higher biomass, light and pigment accumulation PSⅡ electron transport system was not found to be inhibited.