Abstract: According to the geometrical optical principle, a model of cell in Gaussian mode optical beam is established to analyze the cross recovering forces on the cell. The relation between the forces and the cell's radius 2R and distance x0 to the axis of the beam is presented numerically. Gaussian mode optical beam can trap different size cells in the same well width, but larger cell can be more tightly trapped for its deeper well. The design of an optical tweezers is also discussed.