Abstract: The present disclosure relates to a locking and positioning mechanism and a rotational folding positioning apparatus. The locking and positioning mechanism includes a locking knob and a positioning pin. The locking knob is in a threaded connection with a side wall of a support sleeve, and the support sleeve sleeves a stand column; the locking knob can be screwed in and out relative to the support sleeve, and when the locking knob is screwed inward, an inner end of the locking knob presses tightly against the stand column for locking. The positioning pin is coaxially arranged through the locking knob, and the positioning pin can extend inward and outward relative to the locking knob; an elastic member is provided between the positioning pin and the locking knob. The mechanism is compact in structure, occupies minimal space, and is convenient and effortless to operate.