We have studied transmission property of electron in vertical MOSFET (V-MOSFET) from the viewpoint of quantum electro-dynamics. To obtain the intuitive picture of electron transmission property through channel of the V-MOSFET, we solve the time-dependent Schrödinger equation in real space by employing the split operator method. We injected an electron wave packet into the body of the V-MOSFET from the source, and traced the time-development of electron-wave function in the body and drain region. We successfully showed that the electron wave function propagates through the resonant states of the body potential. Our suggested approaches open the quantative and intuitive discussion for the carrier dynamics in the V-MOSFET on quantum limit.