This paper presents the development of a tension force estimation technique based on the acoustoelastic effect of ultrasonic bulk waves for a cylindrical rod in the suspension bridge anchor system under varying temperature conditions. Three Macro Fiber Composites (MFC) are installed on the surface of a mock-up scale rod specimen for generation and sensing of ultrasonic bulk waves. The ultrasonic responses are obtained under various tension force levels and temperature conditions, and the relationship between the time lag of the ultrasonic response and the tension force is established. Subsequently, the temperature effect of the tension force estimation is theoretically investigated and compensated for field application. The performance of the developed technique is examined through the tension force estimation under varying temperature conditions. The uniqueness of the developed technique includes (1) tension force estimation of the mock-up specimen of the real bridge using the acoustoelastic effect, (2) theoretical derivation of the relationship between the applied tension force and the time lag of ultrasonic bulk waves considering the elastic modulus and density variation, (3) theoretical study considering the temperature effect of the acoustoelastic effect and (4) compensation of the temperature effect on the tension force estimation without temperature measurement of the rod specimen.