Pollen morphology of 40 wild populations of Paeonia delavayi was examined using scanning electron microscope. The results indicated that pollen morphology of P. delavayi had distinguished diversity among different groups. The pollen grains were prolate，occasionally perprolate or subspheroidal，3-colporoidate，and the polars were 3-split rotundity. Exine sculptural types include 6 types，i.e. micro-foveolate，foveolate，reticulate，wide-reticulate，regulate-reticulate and regulate patterns. Combined analyses together with macromorphology，the pollen grain morphology has a high correlation with flower color and living conditions. Finally，the significance of systematics and evolution about tree peony was discussed through pollen morphological characters.