To achieve an optoelectronic tracking platform based on biprisms, it is necessary to accurately calculate the angle of the Risley prisms based on the beam direction. This article uses non-paraxial ray tracing method and two-step method to fit the relationship between the angle difference and deflection angle of achromatic rotating biprism using the Neural Network. In solving the azimuth angle and the angle of achromatic rotating biprism, we separate the nonlinear relationship from the linear relationship, which is also fitted by using neural network. Finally, the mapping relationship between the angle of achromatic rotating biprism and the direction of the outgoing beam is obtained. The experiment shows that the exact inverse calculation of angle value of 0.000 1° is obtained under the condition of using only three layers of neural network with 20 neurons.