A power device includes a power tool, a mounting plate, a mounting table, a positioning assembly, and a locking assembly. The positioning assembly includes a positioning piece. A positioning space is formed between the positioning piece and the mounting table. An end of the mounting plate is enabled to be inserted into the positioning space so that the mounting plate is pre-positioned. The locking assembly includes a movable piece and a locking piece. The movable piece includes a support position where the mounting plate is supported and an unlocked position where support for the mounting plate is released. The locking piece fixes at least the mounting plate to the mounting table.