The present disclosure provides a high-voltage isolating device and method. The high-voltage isolating device includes a power module and a shelf. The power module's back panel is provided with a first connecting portion, and the power module's front panel is provided with a first fastening member. The shelf includes a module slot for accommodating the power module. The module slot's rear end is provided with a second connecting portion, and the module slot's front end is provided with a second fastening member. Wherein in a first status, the first connecting portion is matched and connected with the second connecting portion, and the first fastening member is away from the second fastening member, and in a second status, the first connecting portion is disconnected from the second connecting portion, and the first fastening member and the second fastening member are matched and connected together by a padlock.