Abstract: The genetic diversity and genetic structure of 317 Guizhou Kam Sweet Rice germplasm resources and 10 indica rice materials as the control were analyzed by 1 K mGPS SNP chip, and the core germplasm of Guizhou Kam Sweet Rice was constructed and evaluated. The results showed that the 1 K mGPS SNP chip obtained 731 polymorphic SNP loci in 317 samples, the proportion of polymorphic markers was 17.89%, the frequency of minimum alleles was from 0.050 5 to 0.500 0, and the observed heterozygosity was from 0 to 0.694 0. The expected heterozygosity ranged from 0.095 9 to 0.500 0, and the polymorphism information content ranged from 0.091 3 to 0.573 6. NJ cluster analysis based on IBS genetic distance divided 327 rice materials into indica and japonica subgroups, among which 317 Guizhou Kam Sweet Rice were divided into japonica subgroups. Core Hunter 3 was used to set 6 sampling ratios of 5%, 10%, 15%, 20%, 25% and 30% for the original germplasm of Kam Sweet Rice. The t-test of genetic diversity parameters showed that 15% sampling ratio could maintain the maximum genetic diversity parameters, and at the same time, many redundant materials were eliminated. Finally, 47 Kam Sweet Rice resources were identified as the core germplasm of the construction.