A closed-loop stepper motor control system, drive device and automation device, wherein the system comprises a microprocessor (1) compatible with EtherCAT communication protocol functions, an external interface circuit (2) connected to the said microprocessor (1) and communication interface unit (3); the said microprocessor (1) is also connected to a drive circuit (4), current testing circuit (5), as well as an encoder feedback circuit (6); the said communication interface unit (3) is mutually connected to the said microprocessor (1) through the physical layer communication circuit (31); the said microprocessor (1) is also mutually connected to the power supply circuit (7) that provides stable power supply voltage.