Abstract: Fracture is a kind of oil and natural gas storage body with high heterogeneity. Its distribution in the 3- dimension space h as nonlinear characteristics to a certain degree. In this paper, similar dimension statistical method has been used to study the distribution of fracture zone, and the parameter is used to compare the fractures' development of several sand layers quantitatively. It has been proven theoretically that the fractal parameter of similar dimension ca n be used to evaluate quantitatively the filling capacity of fracture zone to 2 - dimension space, and the practical statistic result shows that the level of similar dimension of fracture zone coincides well with the comparing relation of pro duction situation of each sand layer.