The utility model provides a mobile carrying device system for an automobile trial-manufacture general assembly. The mobile carrying device system comprises a general frame, at least four sliding rails and at least two carrying devices. The general frame comprises a carrying device transferring area and an assembling area arranged adjacent to the carrying device transferring area. The assembling area comprises at least two stations arranged in an adjacent mode. The carrying device transferring area and the assembling area are respectively provided with the sliding rails in the transverse direction. The sliding rails are respectively arranged on the stations in the longitudinal direction. The transversely-arranged sliding rails intersect with the longitudinally-arranged sliding rails. The carrying devices are arranged on the sliding rails and can stretch out and draw back vertically. According to the mobile carrying device system, the professional stations can be distributed reasonably, trial-manufacture general assembly of a plurality of sample automobiles can be carried out simultaneously, continuity of trial-manufacture general assembly can be ensured, and production efficiency is high.