In the Tianbaoyan National Nature Reserve,with coarse woody debris(CWD)in the four kinds of different Tsuga longibracteata mixed forests(A-D) as the research object,by the method of natural wind dry and indoor soak,we carried out CWD quantitative analysis and comparative study for water storage capacity in the process of water and dehydration according to types (fallen woods,snags,stumps) and decay classes(I-V,from slight to severe degrees).The results showed that:(1)different T.longibracteata mixed forests arranged order by modified interception amount of CWD:T.longibracteata+Lithocarpus glabra+Pinus massoniana mixed forests(B,14.21 t/hm²)>T.longibracteata+Castanopsis eyrei+Cyclobalanopsis glauca mixed forests(C,7.78 t/hm²)>T.longibracteata+C.glauca+Michelia maudiae mixed forests(D,6.99 t/hm²)>T.longibracteata+Rhododendron simiarum mixed forests(A,4.74 t/hm²);The various types of CWD arranged order by modified interception:Fallen woods(19.579 t/hm²)＞Snags(8.494 t/hm²)＞Stumps(5.661 t/hm²);(2)In the water-absorption process,arrange the water storage capacity and water-absorption rate of the CWD with different Tsuga longibracteata mixed forests according to size:B>D>C>A,while in the water-losing process,arrange the water storage capacity and water-losing rate of the CWD with different T.longibracteata mixed forests according to size:B>C>A>D;(3)The CWD of different decay calsses according to water storage capacity,water-absorption rate and water-losing rate for size:Ⅱ＞Ⅵ＞Ⅲ＞Ⅴ＞Ⅰ.The studies showed that:the size difference of CWD storage of water is connected with the community types,decay classes,water holding capacity of CWD and other factors.The rate of water and dehydration is also closely related to its water-holding capacity,water storage capacity and decay classes.The natural water holdup of CWD is compounded by the increasing decay class.And the decay class of CWD is higher,the change of water storage rate of CWD is more obvious.The differences of decay class of CWD is great influence on its water storage capacity.Fallen woods have the good water-holding capacity,and the total storage of them is much larger than that of snags and stumps,so they have a strong practical ability to intercept rainfall.