Abstract: 【Objective】 This study aims to investigate the genetic diversity of 20 commercial tomato cultivars, screen out tomato varieties with specific disease resistance traits and provide guidance for farmers in variety selection. 【Methods】 SNP markers were used to analyze the genetic relationship clustering, genetic composition, disease resistance genes, and also conduct disease resistance infiltration fragment analysis of 20 commercial tomato varieties. 【Results】 The 20 commercial tomato varieties were divided into two groups, and tomato varieties from the same company were more likely to be grouped together. Among them, Zhongshu 4, Zhongshu 6, and Zhongza 9 from Zhongshu Seed Industry Technology (Beijing) Co., Ltd. were classified into the same type in genetic relationship clustering and genetic composition analysis. In addition, there were genotype differences in the Mi-1.2, Ty-1/3, and Ve disease resistance genes among the 20 commercial tomato varieties. By comparing their genome similarity with the infiltrating donor materials, it was found that most materials contained infiltrating fragments of Mi, Ty-1, Tm-2, and Sw-5. 【Conclusion】 The 20 commercial tomato varieties are divided into two groups, and tomato varieties from the same company are more likely to be grouped together. The specific disease resistance genes and disease resistance infiltration fragments of these materials are of great significance for in-depth understanding of variety germplasm characteristics, promoting agricultural development, increasing farmers' income, and improving agricultural production efficiency.