During full-power operation of the AP1000 nuclear power plant, the noise level in the main control room reaches 62.1 dB, which adversely affects both the working conditions of staff and their ability to communicate. Through frequency spectrum analysis and third-octave band analysis of the noise in the main control room, it was identified that 189 and 313 Hz are two prominent frequency peaks in the noise composition. A comparison of the vibration frequency characteristics of the adjacent rooms, including the main steam isolation valve and safety valve, was conducted. Based on these findings, a specialized high-temperature-resistant dynamic vibration absorber was developed for the main steam pipelines. This device functions by reducing the vibration energy of the pipelines and associated penetrations, thereby mitigating the noise transmitted to the main control room. After implementing the dynamic vibration absorber, a comparative analysis of noise data before and after installation demonstrated a significant reduction in the overall noise level in the main control room, with a noise reduction range of 3–7 dB. The implementation of this solution confirms the effectiveness of the dynamic vibration absorber, providing a technical reference for noise reduction in main control rooms of similar nuclear power plants.