To simulate the stress and deformation during the cooling process of fiber-reinforced-plastic(FRP)structures, a finite element method(FEM)to evaluate residual stress and deformation, which occur by cooling after curing of FRP products, has developed. In this method, orthotropic visco-elastic behaviors measured by creep tests at several temperatures were simply approximated with an exponential function and orthotropic parameters. The relaxation modulus approximated with the exponential function describes the visco-elasticity and the orthotropic parameters describe the orthotropy caused by fibers in the FRP. To confirm the performance of the FEM program, the residual stress and defomation of a coil caoted by epoxy GFRP(glass FRP)pre-preg during cooling were simulated with this program. And it is shown that this simulated residual stress agrees well with the experimentally measured stress.