A Kretschmann configuration‐based surface plasmon resonance sensor has been proposed. The sensor is made up of calcium fluoride prism, silver, silicon, and tungsten di selenide nanolayer. The theoretical and numerical study of SPR sensor have been analyzed by angle interrogation method with the help of MATLAB 2017b. The transfer matrix method (TMM) is the foundation for simulation and a monochromatic light of wavelength 633nm is considered as source. In the proposed device structure, each layer has been arranged in vertical format to improve the electrical and optical properties. The refractive index for analyte is considered as 1.330 to 1.335. Silver (Ag) metal is used for generation of surface plasmons. It has good chemical properties like metallic conductivity, chemical stability, band gap, small work function and acts as an adhesive layer between calcium fluoride prism and silicon layer. To improve the molecular contact and absorption, the transition metal dichalcogenide nanofilm tungsten di selenide (WSe2) is applied at the top. The sensitivity of 367.4 deg/RIU, detection accuracy of 0.4169 deg‐1, quality factor of 193.58, and full‐width half maximum of 1.8985 deg. are obtained optimized performance parameter of the proposed device structure.This article is protected by copyright. All rights reserved.