The invention discloses an online management method of a numerical control machine tool cutter. The method comprises the steps of firstly establishing a numerical control machine tool cutter online management system, establishing a database in a cutter management server, developing a corresponding functional module interface on a workshop tool magazine terminal, programming a sub-program on the numerical control machine tool according to an adopted numerical control system programming rule, receiving and transmitting information between a machine tool and the cutter management server by the cutter management server through calling a function in a serial-port server, performing processing according to the read program data, rewriting or searching the database, and transmitting the searchedinformation to the corresponding numerical control machine tool. Through networking all machining centers and workshop tool magazine terminals, the online management method has advantages of realizingaccurate recording and searching for cutter information, reducing cutter exchange time, sufficiently utilizing the residual service life of the cutter, saving manpower resource and improving production efficiency.