Based on the requirement of speediness and accuracy in practical engineering and Onesky company EPO full voltage monitoring system features, practical engineering overvoltage recognition problems were studied. Using time domain information and frequency domain information got from the interpolation FFT algorithm, an identification strategy prioritized more harmful overvoltage and an identification strategy prioritized typical characteristics were proposed. They solved a kind of misclassification in mixed overvoltage and quickly identifying overvoltage problem in practical engineering. The result indicated that the proposed strategy had certain practical value. Then this paper also laid a foundation for further studying in practical engineering overvoltage diagnosis and identifying.