Isozyme are important biochemical markers for studying population genetic structure in expediting the sampling, evaluation, and use of crop genetic resource. To identify the genetic structure of the rice germplasm in China, we analyzed 6731 cultivars by starch gel electrophoresis for 12 isozyme loci following the procedures of Glaszmann et al. Fifty-two alleles were found from the tested materials, which covered 96.3% of the total 54 Isozyme are important biochemical markers for studying population genetic structure in expediting the sampling, evaluation, and use of crop genetic resource. To identify the genetic structure of the rice germplasm in China, analyzed 6731 cultivars by starch gel electrophoresis for 12 isozyme loci following the procedures of Glaszmann et al. Fifty-two alleles were found from the tested materials, which covered 96.3% of the total 54