The invention discloses a locking mechanism for a door and a window. The locking mechanism comprises a slide rail fixedly mounted at the upper end and/or the lower end of the door and the window. A slide block is slidably mounted on the slide rail, limiting blocks for preventing the slide block from falling off are arranged at two ends of the slide rail, and the limiting blocks are fixed to two ends of the slide rail through screws; a mounting seat is arranged on the wall located on one side of the door and the window, the mounting seat and the slide rail are located on the same horizontal height, and the mounting seat is fixed to the wall through a screw; an electric telescopic rod is connected between the slide block and the mounting seat, and the electric telescopic rod is electricallyconnected to a central processing unit. The locking mechanism for the door and the window is novel in structure. By means of a locking mode of matching the electric telescopic rod, the slide rail andthe slide block, the locking mechanism is high in locking ability. A key hole in the outer side of a door body is removed and the door is opened without a key, so that the conciseness and the attractiveness of the outer side of the door body are improved. The locking mechanism is high in safety performance and has relatively high practicality and good market application prospect.