Abstract: In the process of ocean crust subduction, the ocean ridge always arrives and meets the trench in an angle. The slab window forms if the ocean ridge continues rifting. In the case, the slab will subduct without ridge, but tears or breaks-off. As the result, the slab window is formed. The slab window commonly occurs along the convergent margin. It will change the regional mantle circulation, and leads to such abnormal geological effects as abnormal magmatism, metamorphism, topography, fluid activity and geophysical characteristics. The specific geological effects of the slab window control the distribution of specific metallic deposits, such as gold and copper. This paper made a review of the formation mechanism, geometry and geological effects of the slab window for the purpose to provide helpful references.