Abstract: The karyotypes of five species of genus Ranunculus in Yunnan province of China were analysed.In Sect.Ranunculus,the karyotype formulas of Ranunculus chinensis Bunge and R.cantoniensis DC.were 2n=2x=16=6m+4sm+6st and 2n=4x=32=14m+6sm+12st.The asymmetrical karyotype coefficient of R.chinensis,R.cantoniensis and R.sieboldii Miq.,gradually increased in different population from west to east in China.In Sect.Auricomus,the karyotypes(2n=4x=32=12m+12sm+8st) of R.pulchellus var.stracheyanus Hand.-Mazz.in Zhongdian population was obviously different from that in Qinghai population(2n=4x=32=24m+8sm).The chromosome numbers and karyotypes(2n=40,2n=5x=40=30m+10sm)of R.tangusticus var.dasycarpus(Maxim.)L.Liou and that(2n=40,2n=5x=40=20m+16sm+4st) of R.napahaiensis W.T.Wang & L.Liao are reported for the first time.