In this paper, a trench-based novel structure for high-sensitive surface plasmon resonance sensor (SPR), sensitivity enhancement has been observed and presented. The novel structure provides localization of a large fraction of the light energy inside a layer that is adjacent to the outer surface of a metal coating on the sensor. In this technique, a propagating surface plasmon gets confined typically by illuminating thin, multilayer metal films through the novel structure. The novel structure helps to extend more localization of the plasmonic field into the buffer medium where sensing has to occur. The trench-based SPR sensor has excellent optical properties, further enhanced the sensitivity compared with the conventional SPR. The change chemical parameter result directly gives the change in refractive indexes of sensing materials corresponds to change in radiation wavelength, reflectivity, phase for a specific incidence angle. © 2020 SPIE.