The optical wedges are designed for the measurement of the vacuum ultraviolet laser beam with a large divergence angle and not so good beam quality. Two wedges have been made and constructed, then applied for splitting and measuring a KrF laser beam. Treatment for experimental data obtained has two ways which constitute a complete description of the KrF laser beam: after drawing a one dimensional energy distribution graph of the laser beam we measured the far field divergence angle;then we calculated the uniformity of energy distribution of the KrF laser beam cross section, for this goal, an analysing program has been developed on the bases of the image analyser Magiscan (2).