<p>In response to the demand for hydrogen safety monitoring, this study proposes an optical hydrogen sensor based on surface plasmon resonance enhancement. Traditional palladium film optical sensors have problems such as weak response and susceptibility to interference. This design innovatively uses low refractive index magnesium fluoride as the substrate and combines it with a periodic palladium nanopore array structure. Finite-difference time-domain simulation shows that the structure exhibits a significant redshift in the reflection spectrum after hydrogen adsorption and an increase in reflectivity, with a sensitivity superior to that of traditional planar palladium films. The nanopore array enhances the optical response through local field enhancement and surface lattice resonance coupling. The magnesium fluoride substrate, with low optical loss and excellent light transmittance, further optimizes the plasmon resonance performance. This study provides a new approach for the development of highly sensitive, fast-response, and intrinsically safe hydrogen sensors.</p>