In high energy nuclear collisions one of the most important issues is the baryon transport that occurs at the early stage of the collision. It dominates all of the later processes during the evolution. The information on the baryon physics could be inferred from the measured particle ratios. In this talk we will report the preliminary results, from the STAR Experiment at RHIC, on the mid-rapidity anti-proton over proton ratios from Au+Au collisions at 200 GeV. The ratio as function of transverse momentum, rapidity, and collision centrality will be presented. In addition, we will show the energy dependence of the proton ratios and compare to some theoretical model calculations.