Understanding of gas-phase chemical kinetics in the atmosphere and combustion involves both the study of rates and mechanisms of reactions, requiring ideal capabilities of detection of neutral reactants, intermediates and products. Mass spectrometry, in principle, serves as a universal method to detect multiple species together with relatively high sensibility, selectivity and time resolution by synchrotron VUV ionization, ideal for the chemical kinetics study. Experimental Method:A home-made tubular flash photolysis reactor combined with SR photoionization mass spectrometer (PIMS) has been utilized to investigate the kinetics of radical reactions. Pulsed photolysis laser is used to initiate reaction, while the species emerging from the side pinepole are ionized by synchrotron source. In the meantime, vertically placed reflectron time-of-flight mass spectrometer investigates multiple species (especially many-atoms). The SR PIMS with time-, energy- and isomeric resolution is applicable for the detection of bigger radicals especially some important radicals such as alkylperoxy and aromatic radicals in the atmosphere and combustion. Time resolution for kinetics study: The pulse generator control the overall reaction. The additional part BNC575 can realise the time resolution measurements. The maximal time resolution of the setup is determined by the resolution of the mass spectrometer. In our apparatus, it is usually set to 40 us, which can be improved via upgrade of the mass spectrometer.