Abstract: To protect germplasm resources and provide technical support for native garden species, the breeding system and hybrid affinity of wild Rhododendron irroratum were studied. The experiments included flowering biological characteristics, the characteristics of breeding system and the cross pollination with fine horticultural varieties of Rhododendron. The process of pollen germination and pollen tube growth were observed by fluorescence microscope, and the fruiting and seed setting were calculated. The results showed that（1） the flowering time of R. irroratum dewdrop was from late April to late May, and pollen viability and stigma receptivity decreased gradually with the extension of flowering time.（2）Hybridization index（OCI） was 3, P/O value was 343.47.（3）The main pollinator was Apis cerana. The breeding system was facultative outbred, selfcompatible, requiring pollinators.（4）No apomixis was found in artificial pollination, which could automatically self-pollinate. The fruit setting rates of different strains cross-pollination, strains cross-pollination and selfpollination were 46.96%, 45.03% and 37.16% respectively. The average fruit setting rate of artificial pollination was basically consistent with that of natural pollination.（5）The hybrid incompatibility was observed in the parent for artificial cross pollination. Fluorescence microscopy revealed callose embolism in the pollen tube of the mother, which prevented the tube from extending to the ovary. Through observation, it is found that the difficulty of cross compatibility lies in pollen tube growth process.