Abstract: In this study，the genetic background of polyploidy seedless Siraitia grosvenorii and their parents were revealed by ISSR（Inter simple sequence repeats）molecular marker technique. The results showed that the genetic similarity coefficient between two individuals was from 0.6399 to 0.8566，and the average coefficient between F₁ generation and tetraploid female parent was higher than that between F₁ generation and diploid male parent，which showed that the F₁ generation got more genetic substance from female parent than that from male parent，and the genetic phenomenon showed F₁ generation was apt to female parent. And the average coefficient between F₁ generation and parents was higher or lower than that between parents. According to dendrogram analysis and double principal coordinate analysis，filial generation and female parent arrayed and clustered together，and if genetic distance of male parent，female parent and filial generation was near，they would array together too. So，in general，the genetic phenomenon embodied“filial generation was similar to parents”.

Key words: Siraitia grosvenorii, polyploidy, genetic background, ISSR