Critical plane analysis refers to the analysis of stresses or strains as they are experienced by a particular plane in a material, as well as the identification of which plane is likely to experience the most extreme damage. Critical plane analysis is widely used in engineering to account for the effects of cyclic, multiaxial load histories on the fatigue life of materials and structures. When a structure is under cyclic multiaxial loading, it is necessary to use multiaxial fatigue criteria that account for the multiaxial loading. If the cyclic multiaxial loading is nonproportional it is mandatory to use a proper multiaxial fatigue criteria. The multiaxial criteria based on the Critical Plane Method are the most effective criteria.