Abstract: Residual gas analysis (RGA) is a crucial and widely adopted technique for determining the precise composition, mole fractions, and trace-level contents of gases within sealed environments. In comparison with other analytical instruments such as gas chromatograph, infrared spectrometer, and electrochemical sensor, mass spectrometer offers distinct advantages, including broad applicability, exceptional accuracy, high sensitivity, and rapid analysis. With ongoing advancements in RGA mass spectrometry, this technique has been increasingly deployed for gas analysis across diverse fields. It now plays an essential role in quality assurance and safety monitoring in semiconductor manufacturing, chemical manufacturing, failure analysis, bioprocessing, and related industries. This paper reviewed the research progress on the overall architecture and core components of RGA mass spectrometry systems. A typical RGA mass spectrometry instrument consists of a sampling system, an ion source, a mass analyzer, and a detector. Sampling systems are designed in various configurations, including direct chamber connection, gas-line interfacing, capillary differential sampling for low-vacuum environments, and destructive sampling methods. The ion source predominantly employs electron ionization (EI) technique, which is highly favored due to its suitability for vacuum gas analysis. Current research aimed at enhancing ionization efficiency and ion transmission focuses primarily on innovations in filament materials and ion source structural design. Common types of mass analyzers include magnetic sector, time-of-flight (TOF) and quadrupole mass analyzer (QMA). Among these, QMA has emerged as the mainstream choice for current RGA mass spectrometers owing to its structural simplicity, compact footprint, and rapid scanning capability. The applications of RGA technology across various disciplines were subsequently reviewed. Within the semiconductor industry, RGA is routinely employed for process monitoring and quality diagnostics in processes including physical vapor deposition (PVD) and chemical vapor deposition (CVD). In aerospace engineering, RGA contributes to the reliable operation of high-precision components and aids in prolonging their operational lifespan. For materials science, RGA serves as a critical tool for both assessing material properties and controlling fabrication processes. In the medical field, this technique enables non-invasive screening for specific conditions, such as Helicobacter pylori infection and diabetes. The future development of RGA technology is expected to prioritize several key directions, including improving instrumental sensitivity, developing more accurate quantitative methodologies, and integrating intelligent algorithms to improve data quality. Globally, the high-end RGA market is currently dominated by foreign products such as the SRS RGA series and Pfeiffer’s HiCube Neo RGA, which maintain a competitive edge through superior performance. Although domestic RGA systems have achieved notable progress in the mid-to-low-end market segments, gaps still exist in core component technology and overall system performance. Therefore, technological breakthroughs in key indicators including sensitivity, mass resolution, and data processing are crucial for realizing full technological autonomy of RGA, breaking the existing foreign monopoly, ensuring supply chain security, and promoting technological advancement in related industries.