  We investigate the pure penguin process $B^-\to \pi^-\phi$ using QCD
factorization approach to calculate hadronic matrix elements to the $\alpha_s$
order in some well-known NP models. It is shown that the NP contributions in
R-parity conserved SUSY models and 2HDMs are not enough to saturate the
experimental upper bounds for $B\to \phi \pi$. We have shown that the flavor
changing $Z^\prime$ models can make the branching ratios of $B\to \phi \pi$ to
saturate the bound under all relevant experimental constraints.
