The invention relates to a rapid fusing device, a rapid fusing control method, a DC circuit breaker and a control method thereof. The rapid fusing device comprises a fuse installation branch used for installing a fuse, wherein the fuse installation branch is used for being serially arranged in a circuit. The rapid fusing device further comprises a fusing current generation unit, wherein two ends of the fusing current generation unit are connected to two ends of the installation branch in parallel. The rapid fusing device also comprises a main control unit, wherein the main control unit controls the fusing current generation unit to generate fusing current, and the main control unit controls the fusing current generation unit to generate fusing current flowing through the fuse installation branch when the circuit is required to be cut off rapidly so as to enable the fuse to be rapidly blown. The rapid fusing device is applied to a DC circuit breaker, and can realize rapid fault isolation through controlling active blowing of the fuse.