Abstract: Military, public safety and emergency rescue have put forward an urgent need for the technology of onsite, realtime, accurate and rapid detection. Ambient ionization mass spectrometry can directly analyze sample onsite, and it has characteristics of simplicity, fast, no sample preparation and can be used to analyze gaseous, liquid and solid sample. The research development of ambient ionization technology was summarized in this paper. In the section of laser desorption/ionization source, the research development and application of four ionization source were introduced, including electrospray assisted laser desorption ionization, laser ablation electrospray ionization, laserinduced acoustic desorption electrospray ionization and plasmaassisted laser desorption ionization. In the content of plasma ionization source, the low temperature plasma (LTP) probe was introduced. The protein and peptide could be detected using paperbased analytical devices (PADs) coupled with LTP. In order to solve the floating potential problem in the plasma, the symmetrical or T-shape DBDI was researched. The miniatured LTP was researched aiming to decrease the high voltage in the plasma. In the electrospray ionization source part, the paper spray and syringe spray ionization were introduced, such as detecting some medicines and bacteria. The application of ambient ionization technology in the detection of chemical warfare agents, biology and explosives was introduced. In the part of chemical warfare agents (CWAs) detection, the microhollow cathode discharge plasma ionization source, and the plasma ionization source coupled with mass spectrometry in the lab and the Mini 105 to analyze highly toxic nerve agents (Gseries, Vseries) and blistering warfare agents and the stimulants were introduced. On the basis of plasmaPADs, gold nanoparticlesenhanced iontransmission mass spectrometry for highly sensitive detection of CWAs was introduced. In the biology detection content, membrane electrospray ionization source coupled with miniature mass spectrometry was used to analyze biomarker in the body fluid, and the ambient laser desorption coupled with rapid evaporative ionization mass spectrometry was researched to improve lipidbased microbial species level identification. The atmospheric pressure MALDI and DESI FTICR in the application of mass spectrometry imaging of single cell and biological tissue were introduced. In the explosive detection section, aerodynamic assisted thermo desorptioncorona discharge ionization and dynamic liquid/solid friction assisted desorptionLTP ionization sources in the application of detecting TNT, C4 were introduced. In addition, the testing of repeatability and constancy of DESIMS with reference samples were introduced. In the last, the problems and future perspectives of ambient ionization mass spectrometry were discussed. Ambient ionization mass spectrometry is expected to provide new research ideas in the area of onsite, realtime, online, insitu measurements.