The invention discloses a flushing splash-proof device for knee-joint replacement operations. The flushing splash-proof device for the knee-joint replacement operations comprises an inner protective layer and an outer protective layer made of plastic film materials, wherein the inner protective layer is located in the middle position on the outer protective layer; the inner protective layer is of an arc-shaped groove shape, the two ends of the inner protective layer are connected with two arc-shaped fixing pipes used for respectively clamping the positions, close to the knee-joint, of the thigh and the shank, at least two connection pipes are connected between the two arc-shaped fixing pipes, the two ends of each connection pipe are communicated with the two arc-shaped fixing pipes, and an air-filled pipe is fixedly connected with one connection pipe or one arc-shaped fixing pipe; the bottom of the inner protective layer is provided with multiple liquid outlets in the length direction; at least one liquid suction tube is fixedly connected on the outer protective layer. According to the flushing splash-proof device for the knee-joint replacement operations, the structure is simple, the use is convenient, the inner protective layer and the outer protective layer are in fixed connection; the flushing splash-proof device for the knee-joint replacement operations can be used after direct unfolding and air inflation during use.