  Using the perturbative QCD approach, we studied the effects from hadronic
structure of photon on the pure annihilation rediative decays $B\to\phi\gamma$
and $B_s\to(\rho^0,\omega)\gamma$. These decays have small branching fractions
due to the power suppression by the $\Lambda/m_B$, which make them very
sensitive to the next-leading power corrections. The quark components and the
related two-particle distribution amplitudes of a final state photon are
introduced. The branching fractions can be enhanced remarkably by the
factorizable and nonfactorizable emission diagrams. The branching fraction of
$B\to \phi\gamma$ even increases by about 40 times, and those of $B_s \to
\rho^0\gamma$ and $B_s \to \omega\gamma$ are at the order of ${\cal
O}(10^{-10})$. We also note that the ratio of branching fractions of $B_s \to
\rho^0\gamma$ and $B_s \to \omega\gamma$ is very sensitive to the effects from
hadronic structure of photon. All above results could be tested in future.
