A method for computing the Laue diffraction of an X-ray spherical wave in a single crystal with an inclined step on the exit surface has been developed. The method is based on the use of two approaches to solving the problem: Fourier transformation of the wave function angular dependence in the case of a plane wave incident on a plate-shaped crystal and a numerical solution of the Takagi equations in the step area, where the diffraction parameters depend on the coordinate along the crystal surface. The effect of strong increase in the reflected-beam intensity (by a factor of more than 7 in the maxima) in the transition area, if the step boundary makes a smaller angle with the reflected-beam direction, is predicted based on the numerical calculations. The dependence of the effect on the step-boundary inclination angle is analyzed.