A SnO2-CuO composite nanofiber was prepared by the coaxial electrospinning method. A new thin. film. type hydrogen sulfide gas sensor was designed by coating SnO2-CuO composite nanofibers onto an alumina ceramic tube with Au electrodes by dip. coating method. The crystalline phase and microstructure of SnO2-CuO composite nanofibers were characterized using X-ray diffraction (XRD) and scanning electron microscope (SEM). The influence of chemical composition and thickness of sensitive film on the sensitive mechanism and electrochemical characteristic of SnO2. CuO nanofibers were analyzed. The characteristic tests of hydrogen sulfide sensor including sensitive performance, temperature, relative humidity, dynamic response, interference and stability were carried out by WS-30A type multifunction analyzer in gas sensor test system. The results demonstrated that, when the operating temperature was 25 degrees C. and hydrogen sulfide gas concentration increased from 10 to 60 mg/L, the hydrogen sulfide sensor based on C50 composite nanofibers with 70 nm sensitive film thickness had the best linearity (92.3%) and sensitivity (98.2%). Besides, its highest response values and relatively humidity level were 1080 and 95%, respectively, and its dynamic response time and recover time were 4 s and 12 s, respectively. This sensor showed good anti. disturbance to the gases, such as CO, NO2, SO2, NH3, CO2, CH4 and H-2. The response value of the sensor was attenuated about 9.2% when it was applied continually in the mine about 12 months, and its normal response time was 10.9 months.