In order to recognize the provenances, granularity characteristics of peat ash, and further reveal the paleo-enviromental significance of peat ash. Two peat cores in Hani and Gushantun Peat-land in the west foothill of Changbai Mountain are collected. The results of grain size analysis show that the dominant size of peat ash is 1~350 mum. Which means peat ash is mainly composed of different kinds of silt. What is more, the majority probability cumulative curves for particle size distribution are with two sections. At the same time, frequency distribution curves show unimodal type (10~100 mum) , bimodal type (10~100 mum, 100~1 000 mum) . These show that the transportation ways of peat ash is suspension and saltation. And the grain sizes changed with the hydrologic condition in the peat land. In the dry season, the water power is weak and the peat ash content is relatively fine. But in the wet season, surface runoff carries the coarse particle into the swamp and deposits. Therefore, the peat ash can be used for rebuilding the evolution of paleo-precipitation and it can be a proxy for the summer monsoon. In addition, 9.2 ka, 8ka and 5ka drought events in Holocene are recognized from the grain size changing curve and the curve also reveals a "dry-wet-dry" cycle in the precipitation history. Because these events correspond to the famous cold events, so we may draw the conclusion that dry and cold, warm and wet may be matched in the process of climate change.