A joint exoskeleton auxiliary driving mechanism has a first driving module. The first driving module has a first gear member, a first connecting member, a first rotating driver, a first linear driver, and a first motion element. The first connecting member is disposed on a side of the first gear member. The first rotating driver is disposed on the first connecting member and engages with the first gear member. The first linear driver is disposed on the first connecting member. The first motion assembly is connected to a first power output element of the first linear driver. The joint exoskeleton auxiliary driving mechanism has two degrees of freedom motion function such as forward rotation, reverse rotation, and dorsiflexion or extension, and has the advantages of structural simplification, precise strength controlling, lightweight, and miniaturization.