Four magnetotelluric sounding profiles were designed and relevant 2D electrical structure models were obtained in order to research the electrical structure of crust-mantle in southeast coastal region of South China. The results reveal that the west part of crust in this area became thicker because of the collision and aggregate effect, while the thickness of east section decreased rapidly due to Pacific plate subduction. The lithosphere structure in southeast coastal region of China does not simply have “west thick and east thin” feature.  Lithosphere thicknesses at two ends of research area exceed 100 km.