Using Morlet wavelet transform we investigated the intraseasonal variability of the subsurface temperature in the SCS by analyzing ATLAS mooring data obtained during the South China Sea Monsoon Experiment (SCSMEX). It is found for the first time that subsurface temperature in the SCS exists intraseasonal variability, particularly in winter. The strongest intraseasonal variability ranges from 50 to 100 m with its maximum amplitude about 1.0--2.0℃. The subsurface temperature intraseasonal variability in the SCS is primarily induced by local wind stress curl via adjusting the vertical displacement of thermocline. It reveals the important characteristic of intraseasonal variations in the SCS upper ocean vertically.