Fiber reinforced composites have been widely used in aerospace and aircraft structures because of their excellent mechanical properties and light weight. Glass fiber reinforced epoxy composite truss with square cross section under three-point bending exhibites nonlinear behavior according to finite element analysis. On the Isight platform, a multi-parameter optimization method was conducted to obtain five key geometric parameters of the optimal composite truss, which met the demands of structural stiffness, load bearing and light weight. Nonlinear structural responses of the optimal composite truss were obtained. The results showed that the use of Isight platform has high efficiency and reliability for multi-parameter optimization of truss structure.