The utility model relates to a site operations of transformer substation alarm device violating regulations off side includes rail, monitoring device, alarm device and regulation support, can send acousto optic alarm when the staff stridees across the work area to can be through the picture of monitored control system real time monitoring work area. Monitoring device sets up the entry end at the work area, alarm device fixes on adjusting the support, adjust support ring around setting up in each extreme point department of work area, the quantity of adjusting the support is the even number, the rail encircle to set up in the outside of work area and surrounds the work area, and only the entry does not set up the rail. Be used for transformer substation's operation on -the -spot, remind thestaff not stride across the work area in violation of rules and regulations, improve the security.