A battery cover includes an inner assembly and an outer assembly. The inner assembly includes an upper board defining an L-shaped groove, a bottom board screwed connected with the upper board; and a metal dome fixed between the upper board and the bottom board to pass throughout the bottom board for contacting the battery compartment. The outer assembly includes a front cover defining a first opening thereon, a slide button receiving in the first opening and the L-shaped groove of the upper board to slidably move along the L-shaped groove.