Abstract: Insulated gap is an important component of Electromagnetic Measurement While Drilling (EM-MWD).It is necessary to take not only the length and the insulation,but also the mechanical properties of insulated gap into account when designing and processing.Applying ANSYS,this article analyzes the rule of the influence of the key parameters of insulated gap on EM-MWD signal transmission.According to the analysis,the insulated gap can meet the EM-MWD requirements when the length of it is 0.5m and the resistance value reaches a few hundreds ohms.Based on this analysis,a mining insulated gap is developed,of which the length is 0.5m and the resistance value exceeds 8MΩ.Its mechanical properties are similar to those of drilling pipes.The result of field test shows that the mining insulated gap can be used in engineering practice.