In order to explore the effect of light quality on the growth and development of yellow-leaf pepper plants, we used pepper leaf yellowing mutant yl1 and its wild type 6421 as test materials and treated with different light qualities (white light, blue light, red light, green light, purple light, yellow light and far red light). The changes of phenotypic, physiological and photosynthetic characteristics were studied. The results showed that: (1) blue light and red light promoted the growth of pepper seedlings, while yellow light and far red light significantly inhibited the growth of seedlings. Compared with yl1, 6421 was more affected by different light qualities. (2) The photosynthetic pigment content of the two pepper materials decreased to varying degrees under different light qualities; the total chlorophyll content and carotenoid content of 6421 were higher than those of yl1 under different light qualities. The photosynthetic pigment content of yl1 and 6421 leaves was the lowest under purple light and yellow light, respectively. (3) Blue and green light could significantly increase the net photosynthetic rate (P_n) of yl1, while different light quality treatments significantly reduced the P_n of 6421. (4) Purple light treatment significantly reduced the PSII potential activity (F_v/F_o) and maximum photochemical efficiency (F_v/F_m) of yl1 and significantly lower than that of 6421, but increased the photochemical quenching coefficient (qP) and non-photochemical quenching coefficient (NPQ) to resist photoinhibition damage. (5) Blue, red and green light can improve the activities of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) in pepper, while yellow light is the opposite. In summary, blue light and red light can promote the growth and development of pepper, while yellow light and far red light have a significant inhibitory effect. yl1 has a stronger ability to resist light stress, especially under purple light than 6421.