Objective To observe the effect of different ultraviolet on HaCaT and offer experimental evidences for further studies of the pathogenesis of photodermatitis. Methods Using different dose of UVA and UVB to irradiate HaCaT cell line respectively. 12 hours later, the morphology of HaCaT cells was observed and the sum was calculated. Results The cell linkage was loose and the refraction was weak with some dead cells. The effect of large dosage of UVB was more obvious. Conclusions the effects on keratinocyte after UV exposure are different according to the dose of irradiation, which offers experimental evidences for the further study of the pathogenesis of photodermatitis.