The surface plasmon resonance of Ag nanoparticles (NPs) and SiO2 coating had been extensively employed to improve the photoluminescence (PL) intensity of nanomaterials. In the article, the LaPO4:Eu3+ inverse opal photonic crystals were fabricated via combining a self-assembly process with a sol-gel method. The SiO2 shells were formed on the skeleton surface of LaPO4:Eu3+ inverse opals and the Ag NPs were added into the voids of LaPO4:Eu3+ inverse opals with the SiO2 shells. The influence of the SiO2 shells and Ag NPs on the PL of the LaPO4:Eu3+ inverse opals were investigated. About sevenfold luminescence enhancement of LaPO4:Eu3+ inverse opals was obtained by the coordination action of surface plasmon absorption effects of Ag nanoparticle and silica-coating effects. The luminescence enhancement mechanisms of LaPO4:Eu3+ inverse opals were discussed.