In DEA (Data Envelopment Analysis), the Full Dimensional Efficient Facets (FDEFs) of PPS (Production Possibility Set) play a significant role and have many useful applications. In this research, we, first, provide a detailed characterization of the structure of FDEFs of the PPS with constant returns to scale technology, using basic concepts of the polyhedral sets theory. Then, using the mentioned characterization together with a mixed integer linear programming, we propose an effective algorithm for finding all of the FDEFs of the PPS. We will elaborate on our algorithm by an illustrative example.