This chapter explores microseismic monitoring and stability analysis of underground powerhouses in pumped storage power stations, with a focus on the Huanggou Pumped Storage Power Station as a case study. It begins by discussing the research background and significance, followed by a review of existing stability analysis methods, including conventional monitoring techniques and microseismic approaches. The chapter highlights key challenges that require further investigation. The design and implementation of a microseismic monitoring system at the Huanggou project are then detailed, covering aspects such as system construction, positioning accuracy, and waveform recognition. By analyzing microseismic activity patterns, the study assesses the stability of surrounding rock masses during excavation, correlating observed activity with geological and structural conditions. Integrating monitoring data with stability evaluations, this work offers a comprehensive understanding of rock mass behavior and provides practical solutions for addressing the complexities of underground powerhouse construction. The findings contribute to advancing the application of microseismic monitoring in large-scale engineering projects and enhancing safety during underground excavation.