In order to understand the cables forces and girder forces state of concrete cable-stayed bridge before the cable replacement construction, and to establish the analysis model of the bridge，the influence factors such as concrete creep & shrinkage, stress relaxation of prestressing tendons, element damage, overload of dead need to be evaluated . Creep, relaxation and shrinkage are closely associated with the material nonlinearity which dependent on time and stress history so it’s reasonable to adopt the finite element analysis technology based on elastic-plastic incremental load method. Based on the specified time intervals, the incremental elastic-plastic finite element equilibrium equation is deduced which includes the effect of creep, relaxation and shrinkage. For the time increment step, numeric expressions of creep, shrinkage and stress relaxation are established for beam element. Methods are proposed to analyze the influence of stay-cables damage and overload of dead. The methods will improve the structure state analysis techniques for the concrete cable-stayed bridge in service period.