Abstract: Flow cytometry and K-mer survey methods were utilized to estimate the genome size of Orophea yunnanensis, and analyzed the genome and its characteristics, and Zea mays DNA was used as standards in this study. The results showed that, the genome size of O. yunnanensis was estimated to be approximately 866.53 Mb or 801.96 Mb by flow cytometry; 125.97 Gb original data was obtained through high-throughout sequencing, and approximately high-quality 123.33 Gb clean data was acquired after processing, and this illustrated the sequencing data was good; the genome size of O. yunnanensis was about 782.9 Mb(K-mer=19), the heterozygous rate was about 0.86 %; when K-mer=21, the genome size was estimated to be 782.20 Mb, and the heterozygous rate was about 0.90 %; these suggested the genome of O. yunnanensis was highly heterozygotic genome; the top three species Chieniodendron hainanense, Alphonsea hainanensis and Stelechocarpus burahol were found to be the same family as O. yunnanensis compared using NT database.