Abstract: The paper aims to determine the control effect of 7 fungicides on tomato early blight and screening the best fungicide for it. The experiment was conducted to isolate and purify the pathogen on tomato diseased leaves, and the pathogen was identified as Alternaria solanil. The growth rate method was used to determine the control effect of 7 fungicides on Alternaria. The results showed that after 48 h, the EC50 of Difeno Conazde and Pvrimethanil was 0.27 and 0.81 mg/L, respectively, the virulence index was extremely high, and had great control effect on Alternaria; the control effect of Flusilazole and Kresoxim-mythyl were fine, their EC50 was 1.29 and 1.54 mg/L, respectively, the control effect of Iprodione and Propiconazole were good; their EC50 was 2.07 and 2.79 mg/L; the control effect of Mancozeb was poor and the virulence index was low, the EC50 was 5.17 mg/L. The control effect of the seven fungicides was similar between 72 h and 48 h.