Photo-acoustic spectroscopy can be used to detect trace concentration gas. The total size can be made small, making it possible to realize portable in situ measurement. The critical technology of photo-acoustic detection is the miniaturization of absorption cell and microphone, which determines the sensitivity and volume of the system. Recent progress of photo-acoustic spectroscopy detection technology in miniaturization and integration is summarized. Three kinds of light sources, absorption cells and photo-acoustic resonators are analyzed and compared, respectively. Meanwhile, the latest progress of Beijing Institute of Aerospace Control Devices is also provided. The quartz tuning fork enhanced photo-acoustic spectroscopy technique is taken to realize miniaturization of absorption cell and photo-acoustic resonator. A compact packaged quartz tuning fork coupling with fiber is demonstrated. A Tm/Ho doped fiber amplifier is used to realize the 2 mm wavelength output with the power of 200 mW, and ammonia and carbon dioxide can be measured simultaneously.