Efficient sunlight harvesting is imperative in the design of ideal photocatalysts for both environmental and energy applications. In this study, a wide-spectral-responsive photocatalyst composited of g-C3N4/red P (CNP) hybrid nanosheets was developed by a one-step "green" sonochemical method at room temperature. Ultrasound irradiation causes exfoliation of the layered g-C3N4, downsizing the red P particles and anchoring them onto the g-C3N4 nanosheets to form intimate CNP heterojunctions. As a dual active center photocatalyst, the CNP heterostructures exhibit significantly enhanced photocatalytic activity both for H-2 evolution and bacterial inactivation under visible light irradiation. In addition, the responsive wavelength of this new-fabricated photo catalyst can be extended to 700 nm. The crucial role of type I band alignment between g-C3N4 and red P is illuminated to facilitate the interface charge separation and extend the light response by efficiently utilizing the photogenerated e(-) excited from both g-C3N4 and red P. Moreover, a direct h(+) oxidation mechanism rather than a e- reduction mechanism is also found for bacterial inactivation under anaerobic conditions. This work provides a general strategy to fabricate novel metal-free heterostructures with wide-spectral-responsive photocatalytic activity by taking advantage of the type I band alignment combined with the narrow band gap feature of elemental red P.