Abstract: To solve the problems of low measuring precision,poor stability and intelligence of traditional gas sensor,the paper introduced a design scheme of intelligent gas sensor.The sensor adopts several gas catalytic elements and takes ATmega128 single-chip microcomputer as control core,and uses least square data fusion algorithm to fuse several detection results of gas concentration,which realizes functions of gas detection and information processing.The experiment result showed that the intelligent gas sensor has performances of high measuring precision,long calibration periods and good main-(tainability.) Furthermore,it can overcome the problems of traditional gas sensor.