A computer simulation of small‐angle diffraction intensities is performed for a W/Si amorphous multilayer structure. The different models which are related to different interface structures after annealing are set up. Calculated results show that the existence of silicide interface layers which induces a change of both direction and magnitude of the diffraction amplitude is not always accompanied by a decrease of the diffraction intensity. In some cases, proper thickness and composition of interface layers may increase the diffraction intensity. However, the existence of systematic and random deviations of layer thicknesses always induces a decrease of x‐ray diffraction intensity.