A new method for tracegases analysis-lasermass spectrometry is introduced in this paper. The principles and characteristics of themethod are described in detail, i.e., the coupling of resonance enhanced multiphotonionization (REMPI) with flight-of-time mass spectroscopy. Emphases are on twoapplications: detection and analysis of exhaust gases from vehicle engines and flue gasesfrom waste incinerators. Laser masspectrometry is an effective method for environmentalinspection, especially as an alternative method for toxic dioxin (PCDD/PCDF) analysis anddetection.