Reducing the dynamic responses of structures subjected to environmental loads is always a topic of interest in research and industry. In this study, an improved form of Tuned mass damper (TMD), called Tuned mass-bar damper (TMBD), is studied and applied in passive control of a structure subjected to earthquake loads. Unlike traditional TMD, TMBD consists of a light, non-deformable bar rotating around a point of the bar. The damper and spring elements are located at the two ends of the bar, and the mass of the TMBD is placed at the position of the spring. The parameters of TMBD are optimized based on data from the 1940 El Centro earthquake. Simulation results show that TMBD is effective in reducing the structure's dynamic responses to the El Centro earthquake and other testing earthquakes. Therefore, TMBD can be applied to reduce the vibration of structures subjected to different environmental loads, such as wave or wind loads.