The study on the regeneration population size and the germination rate threshold of rice landraces will provide a scientific basis for the establishment of the size of reproduction population and the critical value of germination rate during the reproduction and renewal of rice landraces germplasm resources in the seed bank. Xianggu, a rice landrace, was used as experiment material, and the effects of regeneration population size and germination rate on the genetic integrity of rice landrace were studied by combined investigation of agronomic traits and SSR molecular marker analysis. The investigation of agronomic traits showed that: to maintain the integrity of Xianggu genetic structure, the appropriate regeneration population size was 60 - 140. Further verification by SSR molecular markers showed that when the regeneration population expanded to 200 plants, it was benefit to guarantee the genetic integrity of germplasm. Meanwhile, the number of alleles, number of effective alleles, gene diversity and Shannon index of populations with germination rate below 60% (50% and ≤ 30%) were extremely significantly lower than those of the control. Except the Shannon index, the number of alleles, number of effective alleles and gene diversity index of populations with germination rate 60% - 70% were not significantly different from those of the control. The Shannon index of the population with 60% - 70% germination rate was significantly lower than that of the control. The result indicated that the optimal regeneration population size of Xianggu was 200 and the critical value of germination rate was 60% -70% during reproductive renewal of Xianggu.