The invention discloses a ratchet mechanism capable of changing direction of rotation, which is characterized in that a ratchet tooth groove (11) on a ratchet (3) is rectangular, namely the two sides of the ratchet tooth groove (11) are mutually parallel straight blocking surfaces; two planes which are intersectant are arranged at the front pawl end of a pawl (5); and one plane is a straight blocking surface with blocking effect and the other plane is an inclined surface with slipping effect. The invention adopts the above technical scheme, the pawl is in direct insert type, the tail end of the pawl is provided with a handle convenient for pulling out the pawl to change the limiting direction, the limited direction of rotation of a turntable can be randomly selected and the pawl is simple to operate when changing the limiting direction; after rotating 90 degrees after being pulled out, the pawl rebounds and does not enter into the ratchet tooth groove, thus cancelling the blocking effect of the pawl, namely realizing free rotation of the ratchet in two directions; and the ratchet mechanism has simple structure and is convenient to operate.