A shelf power supply system has a power supply track and a first power taking head and a retractable power supply track, the first power taking head has an external wiring. The retractable power supply track has a first moving part electrically connected to the external wiring and a second moving part being electrically connected with the first moving part and slideable thereon. The second moving part has a terminal. The invention can solve the problems that the wiring is complex and difficult to hide in the power supply system of the low-voltage lamps installed in the shelves and the laminates, suitable for the shelf support arms with different lengths, the size is small, the operation is very convenient, and one track can power multi-layer lamps, avoiding complex winding in the shelf, which is very simple operation and convenient for hidden installation in the shelf.