When we measure electrical signal based on sampling method, consequences have large errors due to noise. To reconfigure original waveform better and improve consequences accuracy, this paper advances correlation-improve and mean-value method based on traditional cross-correlation theory. The method can use sampling data plenty and reconfigure original waveform accurately for high-accuracy measurement. In addition the method can control harmonic component and overcome frequency deviation when it is the Integral multiple of sampling period. At last accuracy and outstanding of the method is proved by simulation and contrasting effective value.