Some embodiments of the present disclosure provide a knife. The knife includes a handle and a blade, the handle includes a first casing and a second casing that are detachably connected, the blade is clamped between the first casing and the second casing, the blade is provided with a plurality of limiting openings that are arranged horizontally, a limiting structure corresponding to the limiting openings is arranged on the handle, and the limiting structure has a locking position and an unlocking position; when the limiting structure is in the locking position, the blade is fixed on the handle; and when the limiting structure is in the unlocking position, the blade can move forward or backward relative to the handle.