The invention discloses a phototherapy instrument for foot treatment of a patient. The phototherapy instrument comprises a phototherapy instrument body and a base, wherein the phototherapy instrumentbody is fixed on the base, and an irradiation mechanism is arranged on one side of the phototherapy instrument body, the irradiation mechanism comprises a shell, phototherapy lamp holders, movable covers, a movable plate, a supporting plate, a supporting rod, a driving device and a locking device, the bottom of the shell is fixed to the base, the movable plate is placed in the middle at the top ofthe shell, the movable plate is fixed to the bottom of the shell through the locking device, movable covers are symmetrically arranged on two sides of the movable plate, one sides of the movable covers close to the movable plate are equipped with openings, the movable covers are in sliding connection with the top of the shell, and the movable covers are fixedly to the output end of the driving device respectively. The phototherapy instrument for foot treatment of a patient provided by the invention can achieve phototherapy to the feet of a patient in a sitting position, meets the use requirements of part of people, also an achieve all-round and uniform irradiation treatment to the feet of the patient, and the treatment effect of the phototherapy instrument is improved.