The use of carbon fiber sheet (CFRP) to strengthen reinforced concrete members is an advanced engineering strengthening technology, which has been widely used in civil engineering. In this paper, ANSYS software is used to simulate the bending of prestressed and non-prestressed beams reinforced by carbon fiber to analyze and study the mechanical mechanism and reinforcement effect of carbon fiber reinforced concrete beams, and the corresponding load deflection curve is given. The results show that the beams reinforced with prestressed carbon fiber are obviously superior to the damaged beams reinforced with ordinary carbon fiber cloth, which not only improves the bearing capacity of the structures at various stages, but also reduces the deflection of the beams during failure.