A nondestructive testing method for the reluctance measurement of carbide saw blades is proposed, aiming at the problems of small weld volume and large coupling deviation interference of carbide saw blade heads. The finite element simulation model is constructed by reluctance detection circuit composed of saw blade base, cutter head and excitation component. Defect recognition is proceeded by the influence of weld properties on reluctance. And an improved support vector machine is used to effectively reduce the interference of coupling deviation in reluctance measurement circuit. The test results show that this method effectively reduces the coupling interference deviation in the measurement, and provides a solution for the quality detection of small size welds. The accuracy of the experiment is 97.25%.