Abstract: The chromosome numbers of 30 Hemerocallis cultivars were observed and determined by using the conventional squash method. Among them, 8 varieties with different plant types and flower colors were chosen for chromosomes karyotype analysis and cluster analysis, aiming to provide a cytological basis for the classification, identification, and breeding practices of Hemerocallis cultivars. The results showed that there were 20 diploids (2n = 2x = 22) and 10 tetraploids (2n = 4x = 44) among the 30 Hemerocallis cultivars, with the chromosome base of x = 11. ‘Moroccan Sunrise’ and ‘Tropical Surprise’ were tetraploids, which differed from the ploidy registered in the American Daylily Association. The chromosome Numbers of other 28 cultivars were consistent with previous reports. The karyotype types of the 8 cultivars were all "2B" type. The asymmetrical karyotype coefficients of 8 cultivars ranged from 59.58% to 65.35%, none satellite was observed in the metaphase nuclei of these resources. Among the 8 cultivars, ‘Pojo’ had the highest degree of karyotype evolution, while ‘Indian Sky’ had the lowest. The clustering results showed that when the genetic distance was 5, the 8 Hemerocallis cultivars could be divided into 3 categories. The third category only had one cultivar ‘Pojo’, which had the farthest genetic relationship with the other 7 cultivars.