An innovative method that refractive index distribution of single-mode ion exchange is reckoned using an experimental way was proposed and implemented.The key conditions are that a diffusion coefficient must be constant.Then two-dimensional diffusion equation with ion-exchange waveguide was deduced,the presumption of the ion exchange waveguide refractive index distribution of article was fitted.The Lorentz relation solved the optical dispersion problem in sensor test. Experimental results showed that characterization guided mode propagation imaginary part constants of absorption loss by the KK transform.On this basis,the trial of fiber-article waveguide - fiber optic integrated sensor was designed.The glucose concentration was measured and the detection limit was 0.1 μM.The experiments confirmed the validity of the method for a low concentration of trace tests.