  In this paper, I will show how to use $\beta$-deformations to deal with dual
flatness of $(\alpha,\beta)$-metrics. It is a natural continuation of the
research on dually flat Randers metrics(see arxiv:1209.1150).
$\beta$-deformations is a new method in Riemann-Finsler geometry, it is
introduced by the author(see arxiv:1209.0845).
