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This study utilizes a metallic grating structure (substrate is silicon, with a sinusoidal photoresist grating on top of the silicon, followed by a metallic silver grating closely aligned with the sinusoidal photoresist grating, and finally Rh800 dye molecules on top) to achieve resonant modulation and significant enhancement of the photoluminescence (PL) of Rh800 dye molecules at different incident angles by controlling the matching relationship between its surface plasmon resonance mode and the excitation wavelength. The experimental results show that when the plasmon resonance mode is precisely matched with the excitation wavelength, the photoluminescence intensity can be increased up to 22 times; even when there is a certain mismatch in the resonance position, the PL enhancement factor can still reach 14 times. As a control, when an unpatterned metal thin film structure is used, a 5-fold enhancement of photoluminescence can also be achieved. Combined with numerical simulations, the resonance mode characteristics, electromagnetic field distribution, and local field enhancement effect in different grating structures are systematically analyzed and compared with the experimental results. The designed grating structure exhibits excellent optical response control capability in a broad spectrum range, providing greater flexibility for effective enhancement of photoluminescence. This strategy has important application potential in optical sensing, bioimaging, optoelectronic devices, energy conversion, and catalytic reactions. A graphical abstract is suggested.