Non-metallic boron modified graphitic carbon nitrogen (BCN) tube was prepared by a simple hydrothermal method using melamine as initial material and boric acid as boron source. Through thermal treatment, boron was directly introduced into g-C3N4 tube structure. Boron modified could increase the specific surface area of g-C3N4 and enhance its visible-light responsiveness. Importantly, the separation of the photogenerated electrons and holes in BCN tube was significantly enhanced, which can contribute to the improvement of photocatalytic activity. The photocatalytic activity of BCN tube was evaluated by degrading Rhodamine B (RhB) and Methylene blue (MB) experiments under visible light irradiation. The prepared BCN-3 sample (B: 0.36 mol %) showed the best photocatalytic activity when the initial material molar ratio of melamine to boric acid was 1:1. The degradation rate of BCN-3 to RhB was 99.3% under visible light irradiation for 90 min. The catalyst also showed good degradation effect for MB.