The invention provides an automatic passing phase separation control device and a passing phase separation control system for multi-locomotives. The automatic passing phase separation control device comprises a phase separation section functional position signal receiving unit (10) for receiving and recognizing a phase separation section functional position signal, a level acquiring unit (20) for acquiring a level signal of a control handle, and a passing phase separation control unit (30) for receiving the phase separation section functional position signal from the phase separation section functional position signal receiving unit (10) and receiving the level signal from the level acquiring unit (20), outputting a level control signal based on the pulse width modulating form of the level signal according to the received functional position signal to control lifting of the level, and outputting a secondary control signal and a main circuit breaker on/off control signal to respectively control starting and shutting of a secondary machine and the switch off and switch on of the main circuit breaker. The passing phase separation device and system are beneficial to stably finish passing phase separation processes of a single locomotive and the multi-locomotive.