Abstract: Based on the proton transfer ion source and time-of-flight mass spectrometry, the proton transfer reaction mass spectrometer was developed. It mainly consists of hollow-cathode discharge, proton transfer flow tube, ion transmission area and time-of-flight mass analyzer. To increase the ion transfer ratio for high instrument performance, three stages vacuum system was adopted for proton transfer flow tube, ion transmission area and time-of-flight mass analyzer respectively. Furthermore, the ion trajectory among ion transmission area was also simulated and optimized by Simion program. Preliminary experiments for the instrument performance test by toluenes standard samples shows that the linear dynamic rang can cover three orders, the limit of detection reaches at least 5×10^-10, and the resolution is better than 4500.