Abstract: A fixing device for clamping a tissue including a clamp mechanism for closing a tissue, a support mechanism for carrying the clamp mechanism, the support mechanism including a drive assembly for driving the clamp mechanism to open and close; a delivery control device including a push shaft for pushing the fixing device and a mechanism for enabling the push shaft and the fixing device to be separably connected, the clamp mechanism includes a pair of closure members, a guide slot including at least a nonlinear segment in each of the pair of closure members, a pin slidable in each guide slot to drive ends of closure clamping portions of the closure members to move towards or away from each other.