Abstract: 【Objective】 This study aims to screen out the agents that have a good control effect on celery leaf spot (the pathogen was: Alternaria tenuissima). 【Method】 The toxicity of 14 fungicides to the mycelia and spore germination of A.tenuissima were measured in laboratory and the field efficacy test was carried out. 【Result】 Among the 14 fungicides, the best inhibition effect on pathogen mycelia was 3% Metalaxyl hymexazol, 5% Carvacrol, 10% difenoconazole, and the EC₅₀ was 10.8, 19.9, 26.2 μg/mL, respectively.The best inhibition effect on spore germination was 3% Metalaxyl hymexazol, 25% Azoxystrobin, 43% Tebuconazole, and the EC₅₀ was 15.7, 29.5, 38.7 μg/mL, respectively.The inhibition test on mycelia and spores showed that only 3% Metalaxyl hymexazol had the best control effect.And the field efficacy test verified the best control effect of the agent was 3% Metalaxyl hymexazol and 5% Carvacrol, its control effect was 96.3% and 83.9%, respectively. 【Conclusion】 3% alopectyl was most suitable for the prevention and treatment of celery leaf spot in the field.