The Dabei gas field as a tight sand reservoir is controlled by the fracture development which directly affects the discovery and deliverability of the natural gas. The appropriate way to describe the fracture is very important. At present, the fracture spacing is a general method to describe the fracture degree, but its shortage is only suitable for the description of outcrop, core and FIM. A few of drill cores and poor representativeness can not illustrate the fracture distribution in well bore. The fracture analysis by image data requires the skillful analyst and the image data, with the random interpreted conclusion, the high expense of the image data, and absence of image data. So, the concept of fractal is proposed in the research of fractured reservoir. According to fractal concept, the data of conventional logging suite were used, in combination with the logging feature of fracture in the Dabei gas field. The fracture in the goal layer of Dabei area is quantitatively described by the method of R/S. The result which was tested by the data of cores and drilling available, suggests that the method of  R/S  is feasible to quantitatively describe the fractures in the Dabei gas field.