The invention discloses a safe electric water heater. The safe electric water heater comprises a socket arranged in a wall body and a plug matched and connected with the socket; a first inserting andfixing groove is formed in the bottom of the socket; a jack is formed in the middle of the top wall of the first inserting and fixing groove; a first through groove and a second through groove, whichextend upwards and are connected with a first sliding groove formed in the socket in a run-through manner, are oppositely formed in the left and right ends of the top wall of the first inserting and fixing groove; and a sliding plate which can slide up and down is arranged in the first sliding groove. The plug can be fixed safely and stably, and the plug is high in power-on stability; when the plug is inserted in, the plug is locked firstly and then the plug is powered on; in pulling out, the plug is subjected to power down and then the plug is unlocked, so that occurrence of an electric shockaccident in plug inserting and pulling can be avoided effectively; and the whole apparatus is convenient and efficient to use, so that the inserting and pulling efficiency of the plug is greatly improved.