By means of strong data processing ability of personal computer (PC) and Labview platform,a mid-infrared dual-channel differential CH_4detection system is designed and realized. A dual-channel IRGJ sensor (purchased from E2V Company,British,3.31μm and 3. 90μm) is utilized to detect concentration change,Labview and data-acquisition (DAQ) car d (PCI6221) are mainly used for signal sampling and processing,a digital second-order Butterwo rth filter is designed via the platform to increase signal to noise ratio (SNR),and finally the system is integrated with both hardware and software.The developed system possesses funct ions including signal acquisition,filtering,amplitude extraction,concentration calibration, information storage and website announcement.CH_4samples with different concentrations are prepare d,calibration experiments are carried out,and detection precision,stability and detection li mit are measured. Experimental results reveal that the measuring range on CH_4is 0-5%;the maxi mum detection error of this system on 9gas samples is less than 6%.Because of limitation of path-length of the sensor,the detection limit is about 60ppm.Four hours detection on a gas sampl e with a concentration of 2000ppm shows that the detection error is l ess than 10%.Due to high data processing ability and powerful functions unconstrained by system resource,this system shows certain applications in the detection on gas samples under laboratory environmen t.