Alignment space is a metric space which is generated by the generalized error. The sequence structure analysis among the space plays a more and more important role in practice. In this paper, the structures of the sequences between which the Alignment distance is 2 in Alignment space ${F_2}^*$ are studied. Alignment distance distribution is also proposed. And the analytic expression for the sequences pairs between which the length is $n$ and the Alignment distance is 2 is obtained.