A surgical retractor includes an outer ring unit, a tubular retraction membrane made of a resilient material and including an inner surface defining a passageway, and a lighting unit. The tubular retraction membrane has an outer tubular end connected to the outer ring unit and rollable about the outer ring unit. The lighting unit is connected to an inner tubular end of the retraction membrane and includes a light-emitting ring, and a heat-dissipation ring in contact with the light-emitting ring.