In order to improve the mechanic performance, the cure process mechanics are approached to find out the relationships among the viscosity history, void evolution and the ultimate mechanic property of the composite structure. A computer simulation program, on the base of resin flow model, thermal stress model, material model and void model, is developed to simulate the cure process, with which the cure process parameter is optimized to meet this challenge. The information of cure process, which mainly is the viscosity evolution and gel point, is obtained by fiber optic microbend sensor made specially. The reason to sensing and controlling the viscosity evolution is that it can represent the cure degree to some extent, besides, keep the viscosity at the lowest point as long as possible can reduce the void and keep appropriate fiber content in the ultimate composite structure. The data is processed by an expert system based on the computer simulation program, then the expert system give instruction to the temperature controller and pressure controller to regulate the cure process.