Using melamine-cyanuric acid (MCA) supramolecular polymer as a precursor, a method was employed to synthesize graphitic carbon nitride with a large specific surface area and controllable band structure. The band structure and morphology of graphitic carbon nitride (g-C3N4) are closely related to the type of solvent used. By treating it with hypophosphorous acid and subsequent high-temperature treatment for 10 h , the precursor material was calcined to produce graphitic carbon nitride with a hollow tubular morphology. Experimental results demonstrate that this material exhibits outstanding performance in photocatalytic degradation of Rhodamine B and Bisphenol A. This work provides a new and effective strategy for achieving visible-light photocatalytic degradation of organic compounds.