The invention relates to a command transmission method between a spacecraft and a carrier. The command transmission method is implemented based on a command transmission system that comprises a mechanical triggering sub-system and an electrical triggering sub-system. The command transmission method comprises the steps of S1, triggering a first command in the mechanical triggering sub-system, and separately sending the first command to the carrier and the electrical triggering sub-system; and S2, receiving the first command by using the electrical triggering sub-system, and triggering a secondcommand in the electrical triggering sub-system and sending the second command to a sub-system in the spacecraft. High reliable command transmission when the spacecraft and the carrier fly normally orescape during an ascent flying phase by using the way of combining the mechanical triggering sub-system with the electrical triggering sub-system. The method provided by the invention has a redundantdesign of dual-channel, multi-touch and multi-command-center, and completely eradicates the hidden dangers of mistakenly transmission and leaking of the commands.