In order to explore the endangered factors of wild European plum. the characteristics of flower, flowering process and visiting insects were recorded in the natural population through field positioning observation. Pollen viability was determined by four staining methods: TTC, MTT, benzidine-α-naphthol and I₂-KI. The hybridization index and pollen-ovule ratio were used. artificial pollination test and other methods to detect the breeding system of wild European plum. The results showed that:（1） Wild European plum is a bisexual flower with a long flowering period, and the flowering period of the population can last for 10-15 days.（2） The wild European plum has no vitality before the flower is opened. The pollen vigor is the highest on the day of anther cracking. The pollen vigor is obviously weakened with the extension of time. The stigma has vitality before the flower is opened. The flower is open and full bloom, and Its stigma is the most energetic.（3） Gravity slide test, wind-borne pollination can be completely ignored; the main visiting insects are bees.（4） The ratio of wild European plum pollen ovule was 2207.5±677.43,and the hybrid index was 4. combined with the results of artificial pollination test, it can be determined that the breeding system of the species is outcrossed, partially self-compatible, and needs pollinators.