A bounce universe, in which the universe undergoes a period of matter dominated contraction, a bounce and then an expansion to form the observable universe like ours, is constructed from String theoretical elements. A stable as well as scale invariant spectrum of primordial density perturbations can be generated during the pre-bounce phase of matter dominated contraction. Dark Matter evolution is studied in the bounce cosmos and testable predictions are extracted in an out-of-thermal-equilibrium production route for dark matter. I will also report on a few initial attempts to construct possible particle physics models in the bounce universe.