This paper deals with the analysis for long-term behavior of composite girder bridges. Time dependent behavior of composite bridge due to the creep and shrinkage of concrete are analyzed. To consider the varying material properties through the sectional depth, the layer approach in which a section is modeled by imaginary layers is adopted. The element stiffness matrix is constructe according to the assumed displacement field formulation and the creep and shrinkage effects of concrete are considered with the first-order algorithm based on the expansion of creep compliance function. Using the developed algorithm, the long-term behaviors of composite girder bridge are analyzed and the characteristics of time-dependent behaviors following the bridge types are discussed in detail.