In this paper, the enhanced terahertz (THz) electromagnetically induced transparency (EIT) resonance is achieved based on the coupled electric field dropping effect within the undulated meta-surface. It is found that the height difference between the inner ring and the outer split ring could lead to a significant coupled mode with electric field dropping distribution. When the height of the inner ring increases, the electric field of the inner ring gradually cascades to the outer ring just as a waterfall so that the coupling between the two rings in a unit cell and two adjacent units is enhanced. Both the simulation and experimental results show that a nearly 95% transparency window which is twice that of traditional EIT can be observed by applying such coupled electric field dropping effect, which may provide a promising way to develop the high resonance intensity meta-surface in the THz region.