The invention discloses a double-layer tramcar system and relates to the technical field of a public transit system. A track beam is erected at the upper portion of a gate pier. An upper layer tramcar track is installed on the track beam and provided with an upper layer tramcar. A lower layer tramcar track is installed at the lower portion of the gate pier and provided with a lower layer tramcar. An internal power supply system is connected with an external power supply system. The input electric energy is divided into two branches through the internal power supply system, and the two branches are connected with an upper layer tramcar power supply system and a lower layer tramcar power supply system correspondingly. The upper layer tramcar power supply system is electrically connected with the upper layer tramcar, and the lower layer tramcar power supply system is electrically connected with the lower layer tramcar. The double-layer tramcar system is flexible and compact in structure and reasonable in design, the requirement for arranging tramcar lines in a narrow space is met, the scale of the power supply systems is effectively reduced, the power supply requirement for the upper layer tramcar and the lower layer tramcar is met, repeated construction is avoided, and later maintenance is convenient.