The invention provides a substation fire preventing system and method, relates to the field of substations, and aims to solve the problem that a substation strongly depends on a firefighting water supply vehicle. The substation fire prevention system comprises a transformer fire monitoring device and a fire preventing device, wherein the transformer fire monitoring device comprises a master computer and a sensor network; the fire preventing device comprises a water tank, a water reservoir, a water storage well, a transformer, a water pump control cabinet, a first water pump and a second waterpump; a ground electrode body is arranged in the water storage well and connected with the transformer; the first water pump and the second water pump are both connected with the water pump control cabinet; the sensor network comprises a meteorological sensor network and a liquid level sensor network; and the master computer is used for monitoring the meteorological condition of the substation through the meteorological sensor network, monitoring the water level conditions of the water tank, the water reservoir and the water storage well through the liquid level sensor network, and controllingthe water pump control cabinet, so that the first water pump and/or the second water pump can be controlled to open and close.