Abstract: Variation of microspore-derived plant ploidy of Chinese cabbage with different maturation characteristics was investigated by means of DNA flow cytometry and morphological identification.The results showed that regenerated populations from the microspores were generally mixed ploidy.The ploidy distribution varied with maturing accessions.The microspore plants of the middle-to-late-maturing Chinese cabbage had the highest proportion of double-haploid,and the spring Chinese cabbage the lowest among all tested.Some haploid plantlets doubled naturally in tissue culture.It appeared that DNA flow cytometry and morphological observation could be used to determine the ploidy level.