Refractive index is an essential optical parameter of materials. The operating principle of the refractometer is already known for more than hundred years. Refractometer measurement principally consists of analyzing an image which is produced by light reflection. This image analysis is aimed to find the location of the critical angle of total reflection, i.e. the borderline at which the light area turns into the dark area. There are four main types of refractometers: A new method to measure refractive index of glass and water has been documented in this paper. In this study we used a simple, easy, and accurate method to measure the refractive index of silica glass and water depending on measurement of the kinetic energy of laser light (405 nm) with energy (4 mj/s) in air and medium. We found the magnitude of refractive index of water and silica glass is the same as reported before.