Door and window lock

The utility model discloses a door and window lock which comprises a main supporting frame, a lower shell is rotationally arranged in the lower end of the main supporting frame through a rotating shaft, a middle shell is fixed to the upper side of the lower shell, an upper shell is fixed to the upper end of the middle shell, an upper rotating column rotationally penetrates through the side wall of the upper shell, and a lower rotating column rotationally penetrates through the side wall of the upper shell. A control rotary disc is fixed to the end, located outside the upper shell, of the upper rotary column, two limiting supporting frames are fixed in the lower shell, a locking plate movably penetrates through the position between the two limiting supporting frames, one end of the locking plate movably penetrates through the side face of the lower shell, and a transmission assembly used for transmission is installed between the locking plate and the upper rotary column. Preferably, the utility model also rela