Abstract: Compared with the equilibrium equation method, the principle of virtual displacement in the statical analysis of structural equilibrium problems has the advantage that the unknown target force can be solved by only one equation from the principle of virtual work, which means neither the supporting reaction and other unknown forces need to be calculated, nor a system of equations needs to be solved. The difficulty of virtual displacement principle is the calculation of virtual displacement. According to the basic theory of kinematics, the kinematic characteristics of virtual hinge and infinite virtual hinge, and the conversion technique of virtual work, this paper develops a method to simplify the calculation of virtual displacement. It also provides examples of force analysis, two for simple statically determinate structure and one for complex statically determinate structure.