Fuel cell system hydrogen pressure control method and device and vehicle-mounted controller

The invention relates to a fuel cell system hydrogen pressure control method and device, a vehicle-mounted controller, a storage medium and a computer program product. The method comprises the following steps: acquiring a target power value of a fuel cell at a next moment; determining whether the fuel cell is in a load reduction working condition according to the target power value and the current power value; acquiring a target anode pressure value at the next moment according to the target power value under the condition that the fuel cell is in the load reduction working condition; determining a pressure reduction mode according to the target anode pressure value, a forced pressure reduction threshold value and a natural pressure reduction threshold value; under the condition that the pressure reduction mode is a natural pressure reduction mode, the hydrogen ejector is closed, and the hydrogen ejector is opened after waiting for a first preset time; and under the condition that the pressure reduction mode