The invention discloses a portable belt grinding machine for a sealing head. The portable belt grinding machine comprises a grinding mechanism, a moving mechanism and a posture adjusting mechanism, wherein the moving mechanism comprises a flat plate, moving wheel sets, a supporting wheel, moving wheel seats and an auxiliary wheel seat, wherein the moving wheel sets, the supporting wheels, the moving wheel seats and the auxiliary wheel seats are mounted below the flat plate; two moving wheel seats are correspondingly mounted at the bottom parts of the two ends of the flat plate through rotatingshafts; each moving wheel seat is equipped with one moving wheel set, and each moving wheel set comprises two moving wheels which are correspondingly clamped at the inner side and the outer side of the sealing head; a moving motor is arranged on at least one moving wheel seat and is used for driving the moving wheels on the moving wheel seat to rotate; the supporting wheel is mounted at the sidepart of the flat plate between the two moving wheel seats through the supporting wheel seat; the two moving wheel sets and the supporting wheel are integrally clamped at the inner side and the outer side of the sealing head, and thus the flat plate can stably move at an edge opening of the sealing head; and the grinding mechanism for grinding the inner wall of the sealing head is mounted on the flat plate through the posture adjusting mechanism. The machine is suitable for the sealing heads with different size and thickness, and has the advantages of being small in size, light in weight, and portable.