The invention discloses a servo back-flushing device of a dust collector. The servo back-flushing device of the dust collector comprises a back-flushing mechanism, a servo control mechanism, a fixing plate, a horizontal movement device and a vertical driving device, wherein the nozzle of the back-flushing mechanism faces the fixing plate, through holes corresponding to filter cartridges one by one are formed on the fixing plate, and the horizontal movement mechanism and the vertical driving device drive the back-flushing mechanism to move according to a command of the servo control mechanism. According to the servo back-flushing device of the dust collector, the back-flushing mechanism and the servo control mechanism are combined, and the horizontal movement mechanism and the vertical driving device drive the back-flushing mechanism to move freely to the positions of different filter cartridges in a three-dimensional space above the dust collector according to the command of the servo control mechanism, so as to achieve the deashing process; the filter cartridge can be subjected to single or multiple back-flushing deashing operations automatically according to the quantity of the filter cartridges, the quantity of pulse valves is reduced, the volume of an air pocket is reduced, the production cost is greatly reduced and the flexible and high-efficiency dedusting function can be achieved.