The invention discloses a double-track trolley variable-structure steering apparatus. The double-track trolley variable-structure steering apparatus comprises a traction main trolley, a bearing auxiliary trolley and a rotary variable-structure assembly for connecting the traction main trolley with the bearing auxiliary trolley, wherein the traction main trolley and the bearing auxiliary trolley are installed on a track system, and the track system comprises an inner track and an outer track which are oppositely arranged. The traction main trolley comprises a wheel train assembly installed on the track system, an outer track cross beam and an inner track cross beam. The bearing auxiliary trolley comprises an outer track load beam, an inner track load beam and a load beam. The rotary variable-structure assembly comprises an upper rotation base, a lower rotation base, an upper sliding block and a lower sliding block, wherein the upper rotation base is fixedly connected with the upper sliding block, and the lower sliding bock is fixedly connected with the lower rotation base. The invention further provides a double-track trolley variable-structure steering system. The double-track trolley variable-structure steering apparatus can achieve small-radius turning of a double-track trolley, improves the stability of the double-track trolley during turning operation and meanwhile is simple in structure.