The chromosomes of six species from Southwest China, consist of Prinsepia utilis, Potentilla parvifolia, Stellaria omeiensis, Psammosilene tunicoides, Cerastium pusillum and Eremurus chinensis were reported. Chromosome numbers and karyotypes of Ste. omeiensis were first reported in this study. The results were the following: (1) the karyotype formulas and asymmetry were respectively as: Pri. utilis 2n=2x=30=1M+20m+9sm, 2A; Pot. parvifolia 2n=2x=28=21m+7sm, 2B; Ste. omeiensis 2n=8x=72=1M+71m, 1B; There are ploidy changes in same population of Psa. tunicoides, the karyotype as: 2n=2x=14=14m, 1A and 2n=4x=28=28m, 1A. Cer. pusillum 2n=2x=24=24m(2sat), 1A. Ere. chinensis 2n=2x=14=2m+2sm+8st+2t, 4B. (2) Based on these data, the taxonomic and systematic significance of chromosome karyotypes in these species are discussed. It is supported that Pri. utilis is Prinsepia of Prunoideae. The cell ploidy of Pot. parvifolia is mainly diploid or tetraploid. (3) In this study the octaploid of Ste. omeiensis, maximum chromosome number of Stellaria, was first reported. Comparing the chromosomal studies of the Psammosilene and the Silene, it was found that Psammosilene probably were generated by the common ancestor group through aneuploidy. In this study, the presence of 2n=24 chromosome number and a pair of satellites were firstly found in Cerastium pusillum. This study showed that E. chinensis may be dimorphic nucleus.