Abstract: The paper aims to ensure a healthy and sustainable development of Panax japonicus var. major industry in northwest Yunnan. In 2017, we investigated the diseases in 5 contiguous P. japonicus var. major planting bases during the disease peak time using a five-point sampling investigation method, counted the number of diseased plant, and calculated the morbidity and the disease index. There were 3 kinds of main diseases of P. japonicus var. major in northwest Yunnan, including round spot disease, black spot and rust disease. Other diseases also occurred in varying degrees, such as botrytis cinerea, powdery mildew, anthracnose and phytophthora blight. The incidence rate under proper farming operation was relatively lower than that under the intercropping with rhizoma paridis or in observation points with widespread weeds. The most serious diseases of P. japonicus var. major production were round spot disease, black spot and rust disease. Therefore, using proper farming operation, such as designing a shelter and building a cultivation garden in high ground with well- ventilation and drainage condition, could greatly reduce the occurrence degree of the diseases.