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Schematic diagram of the dual-gas sensor system, which includes a gas pretreatment part, an optical part and an electrical part. [Display omitted] • A SPGC and a MPGC were developed for achieving wide measurement ranges. • The developed sensor system is intrinsically safe and explosion-proof. • The developed gas pretreatment module can remove moisture and aerosols. • Use temperature compensation algorithm to adapt to changes in ambient temperature. • The sensor system can operate normally in the laboratory and field deployment. To effectively monitor gas explosion and coal spontaneous combustion in coal mine, an intrinsically safe and explosion-proof dual-gas sensor system was developed for methane (CH 4) and carbon monoxide (CO) measurement. A distributed feedback (DFB) laser was used to scan two adjacent absorption lines (CH 4 : 4284.51 cm−1, CO: 4285.01 cm−1). Two measurement ranges of 0–500 parts per million by volume (ppmv) and 0–300,000 ppmv for CH 4 and 0–100 ppmv and 0–4000 ppmv for CO were realized using a ∼25 cm single-pass gas cell (SPGC) and a ∼25 m multi-pass gas cell (MPGC), respectively. A gas pre-treatment module was used to remove moisture and aerosols from gas samples. A temperature compensation algorithm was adopted to deal with ambient temperature change. Based on the Allan deviation analysis, the limit of detection (LoD) of CH 4 is 0.19 ppmv and the LoD of CO is 0.12 ppmv, respectively, at an averaging time of 0.5 s. A continuous two-day CH 4 measurement was performed to demonstrate the long-term stability and environmental monitoring capability. The sensor system was successfully deployed in coal mine gas analysis at Longjiapu, Changchun City, China. [ABSTRACT FROM AUTHOR]