Seedlings of Elizabeth melon were treated with PP_(333), CCC, PP_(333) + Ca and CCC + Ca . The results showed that the treatment might improve yield, quality and agricultural characters of plant, and reduced infection rate of blight. Infection rate of seedling blight decreased by 20% ~100%. Infection rate of plant blight with the treatment of applying I0 rng/kg PP_(333) was the lowest. By spraying 50 mg/kg CCC, and 150 mg/kg CCC + Ca or PP_(333), the effect of yield increase was most obvious.