The embodiment of the invention discloses an anti-theft device for a power distribution cabinet. The anti-theft device comprises a box body and a box door. Fixing components connected with the box door are arranged on the inner sides of the left and right side walls of the box body. The box body is provided with a driving component used for driving the fixing components to drive the box door to beembedded into the box body. Two fixing components are connected through a gear transmission component. When the device is used, the fixing components are used to embed the box door into the box body.After the box body is closed, the existence of a large gap can be avoided, and the problem that someone viciously uses a crowbar to open the power distribution cabinet can be effectively prevented. Secondly, when the box door is opened, a key corresponding to a key lock needs to be used. Since both the fixing components and the driving component belong to the mechanical transmission, certain force is required to enable the components to continuously move. The problem that an unscrupulous person pries the lock through an iron wire is effectively avoided. The anti-theft performance of the device is more excellent.