In conventional seismic exploration，complex overburden prevents us from imaging the deeper under- ground structure，because near-surface velocity model cannot be efficiently simplified and accurately estab- lished． The virtual source method provides a promising solution，which images below a complex overburden without the knowledge of overburden velocities and near-surface changes． In this paper，the authors simulate the forward modeling under complex overburden with sources on the surface and receivers in the horizontal well， and reset the real sources into the horizontal well using the virtual source method，which subtly avoid the distor- tion effects of the complex overburden． Finally the underground structure can be imaged using Kirchhoff migra- tion，so the feasibility and advantages of the virtual source method are verified．