The utility model provides a device capable of adjusting the center distance of a power feed belt. The device comprises a left mechanism, a right mechanism and a U-shaped movable frame, wherein the left and the right mechanisms capable of adjusting center distance are fixed on a left side plate and a right side plate of the rack of a power feed device; the open end of the U-shaped movable frame ismounted into a fixed frame along the guide groove of the fixed frame; the square end of an adjusting screw is screwed into the square slotted hole of the fixed frame; the shaft shoulder part of the other end of the adjusting screw is inserted into a circular hole concentric with the movable frame; two pin shafts are riveted into the space positions of the movable frame on two sides of the inserted shaft shoulder; support bearings at the two ends of a driving shaft of the power feed belt are mounted and fixed on the left and the right side plates at the other end of the rack; the sleeves of the support bearings at the two ends of a driven shaft are respectively fixed in semicircular holes at the front ends of the movable frame of the mechanisms capable of adjusting center distance on the left and the right sides so as to form two support surface turning points of a driven wheel of belt transmission; and the center distance size between the driven shaft and the driving wheel shaft can be adjusted by adjusting the adjusting screws of the left and the right mechanisms capable of adjusting center distance.