The domain structures in calcium cerium fluorocarbonate mineral series from a rare earth mineral deposit within an aegirine alkali granite massif in Mianning County, Sichuan Province, China, were studied by means of transmission electron microscopy. Many categories of domain structures in this mineral series were observed and in-vestigated, including the microtwin domains of parisite 6R2 and B2S 6R, the antiphase domains of B2S22H. The re-sults show that the antiphase domains which are faults along crystal plane (0001) are formed by the displacement of crystal lattice in c* direction and the displacement is 0.471nm. A new polytype (B4S2 3R) of regular mixed-layer structure with B4S2 type is found in the domain region of mixed layer structure.