Typical feature recognition algorithms in industrial applications are primarily used for solving cases where a feature locates on a single face only. A feature locating on multiple surfaces is quite common in real CAD models, but it has not been received extensive study yet. The reason is because the loop data in current B-rep model is limited to a face only. The aim of this study is to develop a method to search for all kinds of inner loops on a CAD model, including the ones within a face and those across multiple faces. These inner loops are called virtual inner loops because they do not exist in current B-rep model. Several realistic examples are also presented to illustrate the meaning and feasibility of the proposed method.