Large-scale chemical pipelines， influenced by factors such as fluid flow， boundary constraints， and source excitations， often experience vibrations during service. Unlike civil structures， these vibrations exhibit higher frequencies and may involve multiple dominant frequency components. Traditional single-frequency tuned mass dampers （TMD） struggle to achieve optimal control in this context. Meanwhile， the application of multiple tuned mass dampers （MTMD） is hindered by the challenges in determining optimal installation locations due to on-site constraints. This paper explores the mitigation of pipeline harmonic responses using MTMD. Firstly， an on-site measurement study was conducted on a propane dehydrogenation unit in a chemical plant， revealing evident frequency multiples or harmonic phenomena. Subsequently， a finite element model for local pipeline segments was established to analyze dynamic characteristics. A parameter design method for MTMD based on numerical search algorithms was proposed. Lastly， considering the limit of practical installation conditions for chemical pipelines， the impact of MTMD installation positions on vibration reduction effectiveness was investigated. Numerical results show that the vibration of pipelines can be significantly reduced by using MTMD.