In this paper we study the global dynamics of stochastic predator-prey models
with non constant mortality rate and Holling type II response. Concretely,
we establish sufficient conditions for the extinction and persistence in the
mean of autonomous stochastic model and obtain a critical value between
them. Then by constructing appropriate Lyapunov functions, we prove that
there is a nontrivial positive periodic solution to the non-autonomous
stochastic model. Finally, numerical examples are introduced to illustrate
the results developed.