Single layer g-C3N4 and nanorod CsxWO3 are coupled to form a composite photocatalyst. During a simple method, no destruction has occurred and the optimal mass ratio of g-C3N4 is 80% as evidenced by systematic analyses. In comparison to pure g-C3N4 and CsxWO3, the composite exhibits significantly high photocatalytic and photoelectrochemical activity for H2 evolution and RhB/phenol degradation under UV, visible and NIR light irradiation. The enhanced photoactivities are attributed to the strong synergistic effect between the localized surface plasmon resonance (LSPR) and the heterojunction interface sensitization, which results in the improvement of charge carriers generation and separation in the composite.