The　1+1　two-photon　resonant　enhanced　multiphoton　ionization　spectra　of　chlorobenzene　were　obtained　at　the　range　of　262-272　nm　on　the　laser　mass　spectrometer　with　heatable　sample　inlet　system　which　was　designed　by　ourselves.　The　result　shows　that　the　structure　of　the　excitation　spectra　in　this　wavelength　range　represents　the　first　excited　state　1B2(S1)　of　the　chlorobenzene.　14　spectrum　lines　were　assigned.　The　characteristics　of　the　photon　ionization　mass　spectrum　at　266　nm　were　analyzed.　The　non-symmetric　broadening　of　the　mass　spectrometry　of　the　77C6H5+　was　analyzed.　The　relationship　between　the　signal　intensity　of　chlorobenzene　and　the　sample　concentration　was　studied.　It　is　shown　that　the　detection　limit　of　the　chlorobenzene　is　about　ng/L　range.