The creep behavior during unloading process, including state of stress change from compression to tension, has been studied based on experimental results. It was noted that the influence of stress level was simply modeled by stress level at unloaded age without influence of loaded age. The function on unloading process was developed and was demonstrated to be applicable for actual design. Super-positioning method using tensile creep as compensation of decreasing compressive stress can be applied. Since tensile creep model can't be defined beyond tensile strength, individual creep function for decreasing loaded stress was proposed. Furthermore compressive creep is also applicable for super-positioning method and the applied value existed in allowable range.