The invention provides a rapid annular workpiece encasing system. The rapid annular workpiece encasing system comprises a base body frame, a control system, a filtering mechanism, a positioning conveying mechanism, an arm mechanism and a single-layer type case replacing mechanism. The filtering mechanism is used for conveying annular workpieces to the positioning conveying mechanism and removing disqualified annular workpieces. The positioning conveying mechanism is used for guiding and positioning the annular workpieces. The single-layer case replacing mechanism is used for achieving case replacement between full cases and empty cases. The arm mechanism is used for achieving clamping and encasing of the annular workpieces. The work face of the filtering mechanism is higher than the work face of the positioning conveying mechanism. The control system is used for controlling work of the arm mechanism, the filtering mechanism, the single-layer case replacing mechanism and the positioning conveying mechanism. The system can achieve a series of actions including automatic product removal, automatic checking, transposition, automatic case replacing and the like, and the production cost is low.