Systematic multiscale analysis of the power-correlation of SSECI was made on basis of 5-min database. The empirical findings show that under framework of multifractal detrended fluctuation analysis MF-DFA, return series G and absolute series |G| appears to exhibit the no-unique exponent of power-correlation over four magnitudes from 101×5 min to 105×5 min. This exhibits that the different amplitudes have the different properties of longrange correlation. The power-correlation exponents of series G show the wider spectrum than for absolute return |G|. The mean exponent of series |G| appears the stronger positive persistence compared to series G.