A coil rack for transformer including a coil winding seat around which an inner and an outer coil windings are sequentially provided. Axially extended through holes are formed on a bottom of the coil winding seat at positions spaced below the inner coil winding. Stoppers are provided to separately locate radially outside the through holes. Each of the stoppers is provided at a bottom surface with a radially extended open channel of which one end leads to the through hole and another end to an outer end of the coil rack. Free ends of the inner coil winding are separately guided downward via the axially extended through holes and then outward via the radially extended open channels on bottom surface of the stoppers to avoid contact with the outer coil winding and any possible short circuit.