Potato is one of the most important staple crops in the world. China is one of the leading producers of potatoes, but the industry faces soilborne diseases such as Verticillium wilt. Most potato planting areas in China rotate the crop with sunflower which is also highly susceptible to Verticillium wilt. The comparison of the biological characteristics and pathogenicity of different mating types of Verticillium dahliae isolated from potato and sunflower in the major planting regions in China is of great importance. This is to help unravel the diversity in V. dahliae population and the sudden increase in infected fields. The diseased samples collected were cultured on PDA and the growing colony of pathogen isolated. Molecular techniques using specific primers were used to identify the V. dahliae pathogens and their mating type of the isolates obtained from the diseased sunflower and potato plants as well as their planting materials. The data obtained revealed that the dominant mating type population in sunflower was MAT1-1, whiles that of potato was MAT1-2, but Race 2 was the only race type identified for all the samples. There was a significant presence of MAT1-1 isolates present in potatoes, which is a new trend. Conventional crop rotation farming using sunflower is causing an increasing prevalence of MAT1-1 and mating type shift of isolates in potato in these regions.