The invention provides a surgical instrument and a bending control mechanism. The bending control mechanism comprises a turning power input mechanism A, a turning transmission mechanism B, a locking mechanism C and a linear power output mechanism D； further, the turning power input mechanism A and the turning transmission mechanism B which are coaxially arranged have a relative rotating angle range in the circumferential direction； the turning power input mechanism A sequentially rotates in an angle I, an angle range II and an angle III while rotating relative to the turning transmission mechanism B from one end angle to the other end angle within a relative rotating angle range, wherein the angle I or the angle III corresponds to turning； the angle range II corresponds to a locking state. With the adoption of the mechanism, the problem of turning and fixing of the surgical instrument in a human body during surgery can be solved, and the risk of surgery can be reduced.
