Coal-accumulating environments characteristics and coal-forming model of Pinghu Formation (Paleogene) in Xihu Depression have been studied using the drilling data and core data in this paper.The coal seams of the Pinghu Formation in Xihu Depression were formed in peat swamps of supratidal zone and intertidal zone of tidal flat facies, peat swamps of the tide-dominated delta plain and the braided river delta plain. Considering the coal-accumulating environments and the paleostructure effects, the tidal flat-delta coal-accumulating model for Xihu Depression of Pinghu Formation is established. The coal accumulation in the tidal flat and the tide-dominated delta are better than in the braided river delta. The distribution of coal-forming sedimentary system is gradually spread from the lower member to the upper member of the Pinghu Formation. The west slope of the depression has a stronger coal accumulation effects than the east fault-terrace belts of the depression.