Methanethiol has been synthesized by one-step catalytic reaction from H2S-content syngas on K2MoS4/SiO2 catalyst with selectivity over 95% under the optimum reaction conditions of 563 K, 2.0-3.0 MPa and 5-6% H2S content in the feed syngas. The results of XRD and XPS showed that Mo-S-K phase on the surface of the catalyst K2MoS4/SiO2 was responsible for the high activity and selectivity to methanethiol, and which may be restrained by the existence of(S-S)(2-) species.