A screw thread twist-stretch transverse stretch-draw prestress exerting system of an adjustable and controllable bamboo and wooden beam is suitable for a prestress bamboo and wooden beam in the field of civil engineering and solves the problems that an existing prestress bamboo and wooden beam is complex in prestress exerting technology, low in accurate degree, unadjustable in size of prestress during a using process and the like. The system comprises an arc-shaped fixed block of a groove, a bolt, a steel backing plate, a prestressed bar, an anchorage device and the like. When construction is specifically carried out, a line type of the prestressed bar can be selected through arrangement of a proper buckling point of the prestressed bar, the prestressed bar is fixed at the beam end in an anchoring mode, transverse displacement of the prestressed bar is limited through the fixed block of the groove, the fixed block is enabled to move up and down through a nut rotatably marked with an angel, and the prestressed bar is driven to generate transverse relative displacement with bamboo and wooden materials in a pressed area to exert prestress. When the prestress is exerted by the screw thread twist-stretch transverse stretch-draw prestress exerting system of the adjustable and controllable bamboo and wooden beam, a hydraulic jack and other professional stretch-draw devices are not needed, construction is convenient, through the fact that the rotary angle of the nut can be controlled, the size of the prestress can be adjusted at any time in a using process, stress bearing is reliable, and adjust and control are convenient.