Methane supercooling filling system and methane supercooling filling method

The invention discloses a methane supercooling filling system and a methane supercooling filling method, and relates to the technical field of carrier rocket low-temperature filling, the methane supercooling filling system comprises a gas supply device used for providing heat exchange gas and a liquid nitrogen supply device used for providing liquid nitrogen, and further comprises a supercooler shell and a pressurization assembly, the liquid nitrogen supply device communicates with the supercooler shell, and the pressurization assembly communicates with the supercooler shell; a first heat exchanger and a second heat exchanger are arranged in the subcooler shell, the two ends of the first heat exchanger communicate with the liquid methane supply device and the storage container correspondingly, and the two ends of the second heat exchanger communicate with the gas supply device and the atmosphere correspondingly. After liquid nitrogen is introduced into the subcooler shell, heat exchange gas is firstly introdu