Various prestressing methods have been proposed for concrete structures to improve their behavior characteristics. Effective as it is for concrete structures however, the applicability of general prestressing methods is generally limited to certain types of structures, namely newly constructed concrete bridges with sufficient cross-section for placing tendons. Multi-stepwise Thermal Prestressing Method(TPSM) has been developed as a versatile pre-stressing method, which can be applied to various types of existing or newly constructed concrete structures, with a straightforward concept and a simple construction procedure. The TPSM utilizes thermal expansion and contraction of the steel prestressing plate due to temporary heat sources. The general sequence of construction using multi-stepwise TPSM is as in Figure 1. The TPSM has some distinctive advantages that differentiate the method from other general prestressing methods. The main advantage of the multi-stepwise TPSM is that it is applicable to (Figure Presented) various types of structures for various purposes. The field of application range from strengthening of girder bridges to continuation of simply supported girders, and can be applied to existing structures as well as newly constructed structures. The method can also be applied to concrete structures regardless of the sectional shapes. The method is believed to have superior cost effectiveness over the general prestressing methods regarding construction of new concrete bridges. Also, the prestressing force can be dissipated over the anchorages so that there is far less stress concentration as illustrated in Figure 2. Another advantage of the thermal prestressing method is that the prestressing plate, which is a prestressing member equivalent to the tendons, acts as a structural member and contributes to the structural stiffness. TPSM can be applied to continuous bridges without restriction to the number of spans, whereas prestressing methods using tendons are generally limited to number of spans no more than three due to the friction loss. Thermal prestressing method can also be applied to continuation of concrete bridges, by inducing initial stresses at the joined sections. This paper describes the basic concepts of multi-stepwise TPSM and its field of application with some illustrative experimental results. The feasibility of the multi-stepwise TPSM is verified by applying the method to a RC girder specimen. Results from the experiments show that the TPSM is an effective prestressing method for improving the behavior characteristics of concrete structures and may serve as a feasible strengthening method.