The number of chromosomes and karyotype of Hibiscus mutabilis f. mutabilis were analyzed with the root tip squash method. The results showed that H. mutabilis f. mutabilis is diploid, the chromosome number of the somatic cell is2n = 92 and the index of relative length is 16L + 12M 2 + 56M 1 + 8S. The karyotype formula is K(2n) = 2x = 92 =86m + 6sm and the asymmetrical index of the karyotype is 54.54%. The karyotype is 2C.