Multilayer gratings are artificially patterned multilyer thin films with the periodicities both in the lateral and normal directions which renders them attracting for microelectronic and optical applications. A proper structural characterization is of primary importance. To test the capability of the X-ray reflectometry technique to fulfil this task, a tungsten/silicon multilayer grating prepared by electron beam evaporation and electron beam lithography was studied both in the coplanar and non-coplanar geometries., the nominal lateral and normal periods being 800 nm and 8 nm, respectively. The coplanar measurements were evaluated within the dynamical theory of X-ray scattering on rough gratings and provided the structural parameters of a real structure with a reasonable precision which are close to the nominal ones. The results revealed also some imperfections of the deposition and masking procedures which are discussed. The non-coplanar measurements were evaluated qualitatively using three-dimensional constructions in the reciprocal space. The advantage of the technique used is its non-destructive character and a simultaneous access both to the surface shape of the grating as well as to its internal structure.