The invention discloses a DOC quick-ignition heating device and a DOC quick-ignition heating method for a heat management system of a diesel engine. The DOC quick-ignition heating device comprises a DOC carrier, an electric heating wire, an insulating cylinder, a heat preservation cylinder, a vehicle power supply, a DOC inlet temperature sensor, a DOC outlet temperature sensor, an exhaust pipe, atemperature control module and a solid-state relay. The electric heating wire is spirally wound on the outer surface of the DOC carrier and is embedded into the inner wall of the insulating cylinder.The DOC inlet temperature sensor and the DOC outlet temperature sensor are both connected with the input end of the temperature control module; and the output end of the temperature control module isconnected with the solid-state relay. The temperature control module is used for controlling the heating power in a way of controlling the duty ratio of a PWM waveform so as to control the heating process of the DOC carrier in real time. The control method for the DOC quick-ignition heating device comprises the steps of: acquiring data; calculating the data; and implementing logic decision and execution. The DOC quick-ignition heating device disclosed by the invention solves the bottleneck problem existing in exhaust gas temperature control of the diesel engine and widens the control range ofthe exhaust gas temperature.