The invention discloses synchronization method for variable frequency speed control of multiple motors controlled by computer based on network, and relevant distributed control system (DCS). Through RS-232 / field control bus converter, and field control bus, PC carries out serial data communication to each frequency converter, as well as reading, calculating and rewriting operational characteristic parameters, and control parameters of each frequency converter. Thus, the method implements distributed control for synchronous operation of multiple motors, making linear speeds of multiple rollers equal or keep certain speed ratio so as to guarantee normal continuous processing. The invention simplifies system structure, reduces cost of equipment, raises reliability of system and level of control and management as well as saves energy etc.