Abstract：The combination of EMD and wavelet analysis is used to detect the period of VTEC. The possible period of ionospheric activity is detected by analyzing the IMFs under multi-scale with wavelet analysis. The probability can be increased with this new method. The VTEC series at different latitudes released by IGS is used as an example. The feasibility and validity of the method promoted in this paper is proven. The possibility of 6 d, 24 d and others is discovered and a new approach is proposed for period detection of VTEC.