Abstract: The hydrological effects of different mixed forests are studied in this paper,such as the water holding capacity of soil etc.The results were as follows:(1)The biomass and water holding capacities of tree canopy increase with the increase of the proportion of the broad leaved trees in the different mixed types.The biomass and water holding capacities of shrub canopy and herb canopy decrease with the increase of the proportion of the broad leaved tree.As a whole,the water holding capacity of the canopy increases with the increase of broad leaved tree proportion in different mixed types.The biomass and water holding capacities of canopy are biggest when of type E 25%～35%,they reach 72.538 t/hm 2 ,1.992 mm respectively.(2)In different mixed types,type D % ranks first in the existent mass and water holding capacities of the litter layer.It is 12.750 t/hm 2 ,1.645 mm respectively.On the whole,the biomass and water holding capacity of the litter layer increase with the increase of broad leaved tree proportion. (3)The water holding capacities differ among different mixed types.In different mixed types,type D’s water holding capacity is the targest,reaching 392.2 mm.On the contrary,the water holding capacity of type A is the weakest.It is 348.4 mm.(4)In different mixed types,type D’s total water holding capacity is the highest.It reaches 395.691 mm.The lowest one is type A %.It is only 349.608 mm.Type D is 1.13 times of type A.(5)Of the different mixed types,the soil permeability of type C % is the best.Its permeability velocity and permeability coefficient are 10.98 mm/min,4.52 mm/min respectively.Type D is the second.The permeability velocity and permeability coefficient are 10.68 mm/min,and 4.29 mm/min respectively.(6)In view of the water holding capacity of the canopy,water holding capacity of the litter layer,water holding capacity of soil and the soil permeability etc,these indexes strengthen with the increase of the proportion of broad leaved tree basically.With the increase of broad leaved tree proportion,the biomass of tree canopy and the existent mass of litter layer rise.So it will hold more precipitation and reduce the runoff effectively.As a result,it demonstrates a stronger ability to conserve water resource and control the soil erosion.