The invention relates to a desulfurization device and method for a low temperature methanol washing circulating methanol partition extractive distillation tower. The device comprises a partition extractive distillation tower, an extracting agent regenerating tower, a condenser, a reboiler and a refluxing tank, and is characterized in that in the partition extractive distillation tower, a partitionis a rectangular steel plate, the steel plate is connected with the top and the inner wall of a rectification main tower, and the rectification tower is divided into a left rectification section, a right rectification section and a common stripping section; and the partition is positioned on the middle upper part of the rectification main tower, vapor phase extraction openings are separately formed in the top of the left rectification section and the top of the right rectification section, and an extracting agent inlet is formed in the middle of the right rectification section. A methanol/extracting agent mixture at the bottom of a divided-wall tower enters the extracting agent regenerating tower and is regenerated, methanol is evaporated out from the top of the tower, the total sulfur content of the methanol at the top of the tower is smaller than 10 mg/kg, and design requirements of low temperature methanol washing circulating methanol are met. By modification on a traditional low temperature methanol washing thermal regenerating tower, the problem that thiol compounds such as sulfur dioxide and methyl mercaptan are continuously accumulated in a low temperature methanol washng system is solved.