Abstract: In this paper, the dynamical response under the basic state with two-dimensional magne-tohydrodynamic equilibrium in the solar corona caused by the radial ejection of cold mass at the solar surface of the open magnetic field is studied numerically. The results show that: (1) a weak disturbance propagates upwards with the Alfven velocity on the front of loop with high plasma density; (2) the moving velocity of the leading edge of loop increases as the radial distance increases, and the increment is nearly equal to the local velocity of solar wind; (3) the maximum of plasma radial velocity in the loop approaches to the local escape velocity at four solar radii; (4) the feet of loophave not any obvious expansion for the open region with stroni magnetic field. These results may explain the solar prominence and the accompanying coronal mass ejection.