The invention relates to a low heat source magnetic stirring device, which comprises a support, a bearing box, a sealing bucket, a speed reducer and a magnetic transmission device, wherein the speed reducer is connected with a source power motor, an output shaft of the speed reducer is connected with an input shaft, the input shaft is connected with a stirring blade, the magnetic transmission device comprises a drive magnetic rotor and a driven magnetic rotor which are arranged in the support, the drive magnetic rotor is connected with the output shaft, and is coupled with the driven magnetic rotor, an isolation sleeve is arranged between the drive magnetic rotor and the driven magnetic rotor, the driven magnetic rotor is connected with the input shaft, magnetic suction components and magnetic spending components are respectively arranged between the input shaft and the rear end of the bearing box and between the input shaft and the front end of the bearing box, two groups of magnetic slip sleeve components are respectively arranged in the input shaft and an inner cavity of a base body of the bearing box, a magnetic locking component is arranged between the input shaft and the sealing bucket, and a cooling device is respectively connected outside a cavity formed between an inner cavity of the isolation cover, the input shaft and the bearing box and an inner cavity of the sealing bucket. The low heat source magnetic stirring device can effectively improve stirring drive efficiency.