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To study the flowering biology of <i>Rhododendron pulchrum,</i> we used scanning electron microscopy (SEM) and paraffin sectioning to observe the microstructures of its floral organs, a methyl thiazolyl tetrazolium (MTT) colorimetric assay to detect pollen viability in different periods, continuous observations to study flowering phenology, and artificial pollination and a benzidine-hydrogen peroxide method to determine stigma receptivity. <i>R. pulchrum</i> exhibited a centralized flowering phenology. The protogynous stigmas of <i>R. pulchrum</i> were able to receive pollen before flowering. The pollen grains of <i>R. pulchrum</i> fused into tetrads, the average ratio of the polar axis length to the equatorial axis length (P/E) was 1.05, and the pollen viability was highest in the initial flowering period, reaching 88.98%. The pollen/ovule (P/O) ratio was 266–328, and the outcrossing index (OCI) was 4; the vitality of <i>R. pulchrum</i> pollen remained high in the initial flowering and blooming periods. Compared with the lifespan of a single flower, pollen vitality remained high for most of the experimental period, thereby improving male fitness. The P/O ratio suggests that <i>R. pulchrum</i> may have a facultative outcrossing breeding system. The OCI estimation suggests that <i>R. pulchrum</i> is partially self-compatible, most likely requiring pollinators to complete pollination.