Abstract: In this paper,the meiotic process of pollen mother cells and the somatic chromosome number 2n=32 of Pollia japonica Thunb.(Commelinaceae) are reported for the first time.The chromosomes in metaphase Ⅰ possess the configuration of 16Ⅱand the secondary association has also been observed.During anaphase Ⅰ and anaphaseⅡ,lagging chromosomes,chromosomal fragments and asynchronism have been observed and the abnormality rates of both phases are less than 10%.The rate of fertile pollen grains is more than 90%,which is consistent with the cell abnormality rate at anaphase Ⅱ.These results indicate that meiotic process of this species is normal,and the somatic chromosome number 2n=32 is credible.