Abstract: The efficiency of gas extraction is directly decided by the fracture network connectivity rate of gas drainage drilling, in order to quantitatively characterize fracture network connectivity rate, optimize the layout of gas drainage hole, theoretically, based on the concept of drilling fracture rate, we use the new method to calculate 3D connectivity rate by "equivalent volume principle". The fractal dimension was quoted to verify the correctness of this theory. Moreover, in Ji₁₅-14120 mining face at No.8 Mine of Pingdingshan Coal Mining Group, dynamic peer tests of dynamic fractures were conducted during the mining process, and the data were vectorized by the software of AutoCAD. The result shows that using "equivalent volume principle" to calculate the connectivity of Ji₁₅-14120 mining face fracture network is smaller than the traditional one-dimensional connectivity rate because the new method is more in line with actual situation.