A new calculation method of electron transport in a medium with boundaries has been developed. The method is based on the solution of the kinetic equation, written for the segments model in the continuous slowing down approximation. The distribution function is represented in the Fourier-Legendre expansion and the equation has been reduced to a system of recursive relations, which permit calculation of the expansion coefficients. The boundaries of the medium have been considered by introduction of a nonscattering medium into the space outside the slab which led to the dependence of the angular distribution function on the coordinate., The calculational results for the plane case are presented and comparisons of them with experimental data and with the calculations of other authors show good agreement.