The invention discloses a machining device and machining method for surface carved indentations of an archaized wooden floor board. The structure of the device comprises blades, set screws, a rotary knife rest, a worm gear reducer, a servo motor, a nut, a screw rod, an extension spring support, an extension spring, a limiting rolling wheel, a rolling wheel shaft, a swing arm A, a fixed shaft, a fixed shaft support, a conveying belt, a limiting screw, a swing arm B, a support A, a support B, a supporting plate, a roller A and a roller B. The rotary knife rest is of a cylindrical structure and six radial knife grooves are evenly distributed in the rotary knife rest in the circumferential direction. One blade is installed in each knife groove and the lengths of cutting edges of the blades are different. The cutting edges of the blades are arranged in a staggering manner in the axial direction along the rotary knife rest and are spirally distributed on the cylindrical face of the rotary knife rest. The blades at the different positions can be selected, the cutting angles and the cutting machining time of the blades can be controlled, and the running speed of the belt can be adjusted in a stepless mode. The machining device has the advantages that the shape and the distribution of the surface carved indentations of the wooden floor board can be diversified and random, so that a natural effect of manual machining can be achieved with high efficiency and a low cost.