The structural properties of alpha "-Fe16N2 single-crystal films were comprehensively investigated by transmission electron microscopy. The electron diffraction patterns with perfect symmetry of alpha "-Fe16N2 single-crystal in <[(1)over bar 13]>, <[(1)over bar 11]>, [011] and [001] directions were distinctly observed for the first time. It is very interesting that the appearance of Bragg spots along zone-axes of <[(1)over bar 13]> and <[(1)over bar 11]> exhibit bce zero rule; while those along [011] and [001] obey fee zero rule. These results imply that there are two kinds of structures of Fe16N2 which are bcc-related and fee-related, respectively, although the lattice parameters of the bet unit cell remain the same. A discussion about the discrepancy of magnetisation and Mossbauer spectra on Fe16N2 is put forward based upon the observed structural properties.