Abstract: In this study, the breeding system of R. prattii Franch. was preliminarily analyzed by means of pollen-ovule ratio (P/O), hybridization index, bagging and artificial pollination in natural population, and the factors affecting the reproductive success of R. prattii were discussed. The flowering time of R. prattii population was from early May to middle and late June, which last for about 48−55 d. The female and male organs had the same maturity. The pollen vigor kept high at bud stage and 1−8 days after flowering. The stigma was the most fertile in 4−8 d after flowering, with the pollen-ovule ratio (P/O) of 852.97±75.5, the hybridization index of 4. In the bagging experiment, the fruit setting rate of artificial cross-pollination was 97.5%, and the hoverflies were the effective pollinators. The results showed that the breeding system of R. prattii was a cross-pollinated plant, which was self-compatible and needed pollinators. It could provide guarantee for reproduction at high altitude. On this basis, it could provide basic theoretical data for the creation of new varieties, which could enrich new Rhododendron varieties at low altitude.