This study proposed a method to reinforce existed structures. Nonlinear analysis for the rectangle axially loaded column with CFRP considering secondary load was done by the finite element analysis software ANSYS. The ultimate limit strengthen for seven rectangle axially columns with CFRP which compared with normal axial column respectively (one of them is comparative column no secondary) was estimated under different level secondary loads. This paper mainly investigated the influence of CFRP under secondary load. Coefficient of CFRP was given.