The invention discloses a sulfur positioning removal device of a SCR catalyst of a diesel engine. The sulfur positioning removal device comprises a DOC, a DPF, the SCR catalyst, a bypass pipeline with an electric-control regulating valve and a post-processing controller, wherein a gas inlet end of the DOC sequentially communicates with an engine exhaust tube through a gas inlet pipeline and a turbocharger; a gas outlet end of the DOC communicates with the SCR catalyst through the DPF; a gas inlet and a gas outlet end of the bypass pipeline separately communicate with the exhaust tube and the gas inlet pipeline; a temperature sensor I, a NOX sensor I and a DPF regenerated fuel oil spray nozzle are arranged on the gas inlet pipeline; a gas inlet end and a gas outlet end of the DPF are equipped with the pressure sensors; and a gas inlet end and a gas outlet end of the SCR catalyst are separately equipped with a temperature sensor II and an NOX sensor II. In use, the post-processing controller controls the DPF regenerated fuel oil spray nozzle and an electric-control regulating valve according to a condition that whether DPF regeneration is needed or not and an operation condition of the diesel engine, so that high-temperature conditions of SCR catalyst desulfurization are met. With the adoption of the design, economical deterioration degree of the engine fuel oil is relatively low.