The working state of drilling bit is a critical issue in the drilling process. The preliminary design of pressure and torque separation sensor for drilling bit is expatiated herein. The sensor unit is composed of the elastic unit and the Wheatstone full bridge. Under composited load, the theoretical analysis about separating the axial force and torque of drilling bit is discussed firstly. The separation has been achieved by using the Wheatstone full bridge pasted onto the elastic unit. Then the transversal and axial strains distribution of elastic unit has been calculated and analyzed by ANSYS software, when the bit is under axial force and torque. Based on the calculation and analysis results, the sensitivity and accuracy of the sensor’s whole measurement chain can be reckoned. Meanwhile, the calculation and analysis results can also give good suggestion about the positions where the strains gauge should be pasted. Finally, it has been proved that this solution can meet the preset requirements very well. The working state of drilling bit is a critical issue in the drilling process. The preliminary design of pressure and torque separation sensor for drilling bit is expatiated herein. The composer load is composed of the elastic unit and the Wheatstone full bridge. the theoretical analysis about separating the axial force and torque of drilling bit is discussed first. The separation has been achieved by using the Wheatstone full bridge pasted onto the elastic unit. Then the transversal and axial strains of the elastic unit has been calculated and analyzed by ANSYS software, when the bit is under axial force and torque. Based on the calculation and analysis results, the sensitivity and accuracy of the sensor’s whole measurement chain can be reckoned. Meanwhile, the calculation and analysis results can also give good suggestion about the positions where the gauge gauge should be pasted. Finally, it has been verified that this solution can meet the preset req uirements very well.