Fractures in rocks greatly affect their elasticity moduli such as bulk modulus,shear modulus,Poisson's ratio and seismic wave velocity;and the change of such kind will differ with types of liquid in fractures.If seismic method can detect the changing of elasticity modulus in target strata,it will no doubt help us further understand the development of fractures.Previous study only focused on vertical and horizontal fractures,but the fractures occur as more forms of distribution.The paper studied the elasticity modulus and fracture density of the rocks which contain both fluid and no fluid only under the condition that fractures are randomly distributed.