Parameters of homemade proton transfer reaction mass spectrometry(PTR-MS)for on-line measurements of volatile organic compounds(VOCs) restricted in“Integrated Emission Standard of Air Pollutants”(GB 16297-1996) were optimized and measured. The individual VOCs in pure N₂ were measured at E/N=144 Td by PTR-MS and the results show that the main ions are the protonated compound and few fragmentations exist. The sensitivity and limitation of homemade PTR-MS was obtained to 11 VOCs. The efficiency of the catalytical converter in gas inlet was tested. The precision of the PTR-MS was discussed. The results show that the homemade PTR-MS is a simple and effective tool for real time monitoring the VOCs restricted in“Integrated Emission Standard of Air Pollutants”.