The invention relates to the field of train air conditioning control, in particular to a train door control method and a train door control system. The train door control method comprises the steps that a differential pressure value between the inside and outside of a train car is obtained after receiving an instruction of opening a door, an instantaneous predicted differential pressure value at the moment before the actual opening of the door is obtained according to the differential pressure value, and when the predicted differential pressure value is lower than a door opening differential pressure threshold value, the train door is started to open. The instantaneous differential pressure value is predicted when the train door is opened, and when the instantaneous predicted differentialpressure value is too large, a solution is provided to prevent the train door from failing to be opened.