Abstract: It is necessary to measure laser orientation in some applications such as laser reconnaissance and alarm. Based on the analysis of interference stripes of equal thickness generated by the parallel laser on optical wedge, the relation of the stripe spacing and laser incidence angle is obtained, and a model of determining the laser incidence direction is presented by means of the measurement of spaces between interference stripes on the adjacent three wedges, then the detecting principle of the model is demonstrated in detail. A multiwindow design for laser orientation detection is given, which is composed of nine optical wedges and can detect laser incidence angle in hemispheric space. The theoretical calculation shows that the design is feasible. The design has more advantages as compared with the existing ones in some aspects such as detection accuracy, reaction speed and system composition.