Based on two methods of Sieving and Pollen-slide, the author designed different size method of charcoal analysis to extract and count different fragment charcoal from loess'paleosol and culture layer. Sieving method is used to extract big fragment of charcoal (the size is over 125 ?) as the proxy of local fire regime;while Pollen-slide method can be used to get small fragment of charcoal (the size is lower 125 ?) as the proxy of regional fire regime. The different size method of charcoal improves the precision of the charcoal analysis and enriches the con-tenl on the study of fire history. The method provides a good way to reconstruct the fire variation and an important approach to study the vegetation history and ecological characteristic on the Loess plateau. Furthermore, the method can make great sense to understand the climatic variation and discuss human activity and their impaction to environ-ment