The genus Oxalis contains important species worldwide with great economic and edible values. However, the testing guidelines have not been furbished, especially in China. Oxalis germplasm, including 60 species and 125 varieties, was collected from home and abroad and extensive field trials and phenotypic observations were conducted along with quantitative taxonomy, observations, correlation analysis and cluster analysis. Under the test guidelines of the International Union for the Protection of New Plant Varieties (UPOV), general guidelines for testing for distinctness, uniformity, stability (DUS) of new plant varieties, and Japanese test guidelines for DUS of Oxalis, 96 test characteristics (38 qualitative characteristics, 28 quantitative characteristics and 30 pseudo-qualitative characteristics) were determined as DUS test characteristics of Oxalis. Each test characteristic was scientifically graded and accurately described, and standard varieties and characteristic diagrams were provided for some characteristics. The guidelines for testing DUS of new plant varieties of Oxalis provide a standard for examining and testing new varieties of plants.