Midinfrared spectral region is favorable for high sensitivity trace gas detection. The development and characterization of a compact midinfrared laser spectrometer for high resolution spectroscopic detection of trace gases is reported. Continuouswave midinfrared radiation is generated by differencefrequency mixing of outputs of two commercial narrow linewidth diode lasers. A maximum midinfrared radiation power of 1 μW at 3.31 μm is generated, and the wavelength tuning region is around 3.2 μm to 3.7 μm. The highresolution spectroscopy capability of this spectrometer is evaluated by trace CH4 measurement, the line at 3 028.751 cm－1 of v3 fundamental vibrational band of CH4 is chosen as target analysis line for this line is relatively free of interference by other gas species. The detection sensitivity for CH4 is estimated to be 0.8 ppm for 10 cm optical path length at atmospheric pressure, and the limitation is supposed mainly from the etalon noise of optical surfaces.