【正文】 on, then transmit the converted data into binary format by calling a subprogram of doublebyte multiply. We need three storage units to hold these data because they are 24 bits data in binary format. Next, system will transmit these binary format data into binarycodeddecimal format by calling a subprogram of triplebyte to binarycodeddecimal. In the last step, paring the value with preset threshold value to decide if the system should send an alarm signal. In the meantime, these data will be sending to host puter above ground through RS485 serial munications unit. Still, the system will send a positive pulse to reset the watchdog timer every sec. the Crystal Oscillator frequency of the SCM adopted in this system is 12MHZ, with timer/counter TO, working in mode 1(16bit timer/counter), its maximal timing interval is about 66ms, so the system will send a feeding dog signal to watch dog circuit every 66ms. 5 Conclusions In this study, an intelligent gas detecting system is presented. It can be used to realtime monitoring the methane gas concentration . The measuring scope of this system range from zero to 2 percent, the sensitivity of the sensor reach to percent. It is equipped with the quick speed and high performance 12bit A/D converter, the operating environment temperature ranged from 20℃～ +70℃ . Still this system features with high reliability, easy to operate, high performanceprice ratio. In this paper, the total plan and software and hardware design of a gas detecting system are presented, by using Proteus to test hardware circuit and using Keil to test assemble language source program, the simulation test result shows this system is of high accuracy, quick response and is feasible. References 1. Li, .: Analysis on relationship between economic growth and coal consumption. Economic Tribune 458, 52–53 (2021) 2. Luo, Z.: Optimum utilization of coal resources in western region of China. China Mining Magazine 10(1), 36–39 (2021) 3. Yu, .: Handbook of Coal Mine Gas Disaster Prevention and Utilization. China Coal Industry Publishing House (2021) 4. Zhou, .: Causes for Extremely Large Methane Explosion in Gengcun Coal Mine and the Preventive Measures. Safety in Coal Mines 32(3), 32–33 (2021) 5. Wang, K., Hao, N.: Conception of Coal Mine Safety Comprehensive Early Warning System. Safety in Coal Mines 39(11), 103–105 (2021) 6. Yan, ., Zhang, L.: Design of Portable Methane Detection Alarm. Alarm. Safety in Coal Mines 39(9), 32–33 (2021) 7. Yu, .: Applications of SingleChip Microputer used in the Control System. Publishing House of Electronics Industry (2021) 8. Sun, ., et al.: New Type AT89S52 Serial SingleChip Microputer and Its Application. Tshinghua University Press (2021) 9. Wang, .: Theory of AT89 serials Single Chip Microputer and Interface Technology. Publishing House of Beihang University (2021) 10. Faizah, .: Room temperature multi gas detection using carbon nanotubes. European Journal of Scientific Research 35(1), 142–149 (2021) 11. Li, ., Hu, Y., Li, T.: Detecting System of Methane Based on Infrared Technology. Safety in Coal Mines 39(11), 63–66 (2021)