The invention is applicable to the technical field of automobiles, and provides an upgrade rollback method and system and terminal equipment, and the method comprises the steps: receiving an upgrade rollback request; searching a backup mirror image address according to the upgrade rollback request; starting an upgrade rollback program, downloading a backup mirror image file according to the backupmirror image address, and transmitting the backup mirror image file to a target ECU; performing cyclic redundancy check according to the backup mirror image file, and judging whether the cyclic redundancy check is passed or not; if the cyclic redundancy check is passed, determining that the cyclic redundancy check is passed; modifying storage records if so, marking active partitions, finishing rollback operations, searching, downloading and transmitting a backup mirror image file through the vehicle-mounted gateway equipment; transmitting the backup mirror image file to the target ECU for version recovery, after rollback, marking the active partition and modifying the storage record An automobile can recover the previous version locally, operation and maintenance personnel do not need tocarry out rollback operation, the version recovery efficiency is improved, and cost is reduced.