This work fabricates a plasmonic lithium niobate substrate with metal nanoparticles (MNPs) to enhance electromagnetic field interaction and diminish lifetime with concentration dependence. The enhanced photoluminescence (PL) from dye molecules in lithium niobate substrate and shortened lifetimes associate with plasmon resonance arising from the metal nanoparticles (MNPs) layers. We experimentally and numerically verified that the surface plasmon coupling between MNPs potentially influences PL reactions. The remarkable enhanced PL of deposited MNPs substrate can be achieved by increasing absorption. The fabricated structure can help tune the surface-enhanced electromagnetic field. The Raman signal of rhodamine 6G dye and PL intensity of DCJTB (4-(dicyanomethylene)-2-t-butyl-6-(1,1,7,7-tetramethyljulolidyl-9-enyl)-4H-pyran) molecules in the fabricated substrate are enhanced 13 times and 10.26 times compared to untreated. Besides, the lifetime is reduced by 22.63%. This work is a perspective method for designing a PL-active lithium niobate substrate using photoinduced metal deposition with concentration dependence.