The invention relates to a connecting unit of a sliding groove type space self-reconstitution cell robot. The connecting unit is characterized in that the appearance of the connecting unit is a regular hexahedron, the regular hexahedron comprises six connecting surfaces, two sets of driving connecting discs, a connecting block, four sets of random driven connecting discs, a guide rail supporting frame and an active connecting mechanism, wherein the two sets of driving connecting discs are correspondingly arranged on one set of opposite connecting faces of the six connecting faces, and are fixedly connected based on screws through four sets of cuboid connecting blocks which are uniformly distributed along the circumference, and the four sets of random driven connecting discs are arranged onother four connecting surfaces except the set of opposite connecting surfaces which are occupied by the driving connecting discs and are fixedly connected or dismounted by using screws according to the connecting requirements. The connecting unit has the driving connecting function in the two opposite directions, moreover, mutual influence does not exist in the connecting process, so that the function adaptability of the connecting unit is enhanced, the connecting strength of the driving connecting mechanism is large, separation of connecting ports is the inverse motion for the connection ofthe connecting ports, and the self-reconfiguration time is saved.