In view of the flaws found in professional 3D scanning systems which require a lot of advanced and expensive equipment, a proposal has thus been made of a simple 3D scanning system, which consists of two ordinary cameras, a level gauge, a computer and an electrically controlled track capable of translation and rotation. Meanwhile, an imaging model has been constructed for a detailed analysis of the relationship between the real world coordinate system and the computer image pixel coordinate system. The feasibility of the model can be verified by exemplification, thus effectively reducing the cost of the 3D scanning system.