Nowdays, the study of measurement of the biological field focuses on the research of improving surface plasmon resonance (SPR) in the fields of integration and detection sensitivity. We designed a kind of grating connected surface plasmon resonance sensor. Theoretically, we analyzed the wave vector and the effective refractive index relations with the diffraction grating structure. Then we obtained the nanoparticles enhancement SPR structure with a resolution 10 times higher than that of traditional SPR sensors. Also, we used the finite-difference time-domain (FDTD) analysis and simulation which showed that it was obvious with coupling effect by the nanoparticles enhancement SPR structure that the reflectance spectral bandwidth results validated the structure significantly which improved the sensitivity. Experimental results showed that the dynamic response of the designed sensor reached 10–6 RIU (refractive index unit). This study has the certain significance to long-distance and special sensing applications.