The invention relates to a connecting unit of a sliding-groove-type space self-reconfiguring cell robot. The connecting unit of the sliding-groove-type space self-reconfiguring cell robot is characterized in that the connecting unit is in a regular hexahedron shape and comprises six connecting faces, two sets of active connecting discs, connecting blocks, four sets of random passive connecting discs, a guiding rail support frame and an active connecting mechanism; the two sets of active connecting discs are arranged on one group of opposite connecting faces of the six connecting faces and fixedly connected through the four sets of cuboid connecting blocks arranged evenly along the circumference by depending on screws correspondingly; and the four sets of random passive connecting discs arearranged on the four connecting faces except for the group of opposite connecting faces occupied by the active connecting discs and are fixedly connected or dismounted through screws according to theconnecting needs. The connecting unit has the active connecting functions in the two opposite directions, mutual influence in the connecting process is avoided, the functional adaptability of the connecting unit is enhanced, the connecting strength of the active connecting mechanism is large, interface disengagement is the inverse movement of interface connection, and the self-reconfiguring timeis saved.