  We study the precision of parameter estimation for dephasing model under
squeezed environment. We analytically calculate the dephasing factor
$\gamma(t)$ and obtain the analytic quantum Fisher information (QFI) for the
amplitude parameter $\alpha$ and the phase parameter $\phi$. It is shown that
the QFI for the amplitude parameter $\alpha$ is invariant in the whole process,
while the QFI for the phase parameter $\phi$ strongly depends on the reservoir
squeezing. It is shown that the QFI can be enhanced for appropriate squeeze
parameters $r$ and $\theta$. Finally, we also investigate the effect of
temperature on the QFI.
