Abstract: The characteristics and influential factors of reser- voirs of Member 3 of Shahejie Formation in the area of Leng35 wellblock,Westen basin of Liaohe are studied by core,casting thin section,X-diffraction,porosity and per- meability analysis,mercury intrusion method etc.The re- sult shows the deposition environment of the area is a con- tinental lake deposition environment in partly damp and partly arid lower than cold geologic climate of temperature condition.The reservoir sandstone bodies can divided into two types:The submarine gravity flows and fan in the bottom of lake.Reservoir rocks are primarily litharenite feldspar and mixed sandstones;the pores of reservoirs don 't grow and distribute non-uniformitly,they are principal ly micro-thin and extremly-thin pore throats.As a whole,the reservoirs possess middle-low porosity and specially low permeability,physical properties decrease a- long with depth and that of the south is better than the north.LithologicaI character,sedimentary facies belt,filled -pore matter,separation,diagenesis are the factors influ- encing the reservoir ability.