Abstract: 108 single-sporangia isolates of Phytophthora capsici, which can cause capsicum blight, were collected from several areas in Jiangxi Province and purified, the bioactivity of flumorph against different stages of Phytophthora capsici was compared in vitro. The results showed that flumorph had significant inhibitory effect on the 3 different growth stages of the strain, mycelial growth of pathogen was affected by flumorph, with a mean EC₅₀ as 0.18159 μg/mL, ranging from 0.07852 μg/mL to 0.38622 μg/mL. The producing of sporangia was more sensitive to flumorph, with a mean EC₅₀ as 0.01588 μg/mL, ranging from 0.00251 μg/mL to 0.03943 μg/mL. The germination of zoospores of Phytophthora capsici was most sensitive to flumorph, and EC₅₀ distributed from 0.00156 to 0.00965 μg/mL with a mean value of 0.00515 μg/mL. Normal distribution analysis showed that the sensitivity of these isolates to flumorph was fitted well with a normal distribution function, and there was no strain of capsicum blight pathogen that had resistance to the fungicide.