Abstract: The automatic switchover without off-blast monitoring system of mine main ventilator which took KingView 6.53 software as upper computer and Siemens PLC of S7-300 series as lower computer was presented.The structure of the system,hardware and software design were analyzed,the paper focused on the switchover process of main ventilator with one click.Compared with the traditional way,it accomplished non-transfinite of gas and smooth transition of air volume.