Abstract: Studied on the symptoms, pathogenic morphology of potato gangrene, the results showed that the symptoms of potato tubers were round, oval, or irregular, sunken lesions formed at the umbilicus or buds. These lesions gradually expanded to form khaki, lavender sunken lesions, in size from 1 to 3 cm. Small black bodies were observed in the center of the lesions. Isolates of Phoma spp. were isolated and purified from twenty-six samples of tuber rot of potatoes in Gansu Province. The morphologic characteristics, pathogenicity, symptoms, biochemistry characteristics and ITS sequence analysis of isolates all suggested they were Phoma foveata, which showed the rot of potatoes was caused by the P. foveata and the disease named gangrene. 30% propiconazole·difenoconazole, 35% carbendazim sulfonate, 5% Junduqing, 10% difenoconazoleyl and 32.5% difenoconazole·azoxystrobin had a better inhibiting action to P. foveata and the EC₅₀ were 2.43×10^-5, 1.77×10^-2, 7.40×10^-2, 1.31×10^-2 and 2.31×10^-1 μg/mL, respectively. The optimum temperature for mycelial growth and conidia germination were 20℃. There were difference on the color, size and edge of colony among different media, but the PDA media was the optimum for mycelial growth. The conidia could germinate under pH 3-10, and pH 6 was the suitable range for germination. The paper was the first report for potato gangrene in China and the results helped to control this disease in Gansu Province.