A rotatable electric plug includes a plug housing including a sleeve body, a plug module including a mounting body and at least a protruding pin, and a limiting assembly coupled to the sleeve body and the mounting body. The mounting body is rotatably coupled in the sleeve body that a rotational movement of the mounting body is reversible. The mounting body has a first side and an opposed second side that a portion of the protruding pin is extended from the first side of the mounting body. The limiting assembly is arranged to block the plug module from rotating infinitely at the plug housing in one direction. The rotatable electric plug has the advantages of enabling the reversibly rotational movement of the plug module, enhancing the rotational movement of the plug module, retaining the plug module at an angular angle, and preventing the plug module from being infinitely rotated.