The invention provides a regenerative brake control method and a regenerative brake control system for trains. The regenerative brake control method includes acquiring a second traction network pressure of a train according to a first traction network pressure, a driving route, substation distribution information, station locations and starting/braking information of the train, wherein the first traction network pressure is a traction network pressure of a substation direct-current bus corresponding to the train, and the second traction network pressure is a traction network pressure at a train pantograph; if determining that the second traction network pressure is within a preset range, starting a regenerative energy absorbing device to complete regenerative brake control of the train. The traction network pressure at the pantograph is calculated according to the traction network pressure at the direct-current bus, the driving route, the substation distribution information, the station locations and the starting/braking information; when the traction network pressure at the pantograph is within the preset range, the regenerative energy absorbing device is triggered to complete theregenerative brake control; the problem that regenerative energy absorption of the train cannot be realized due to differential pressures of traction networks is avoided, and the frequency of mechanical braking of the train is reduced.