Four theorems about four different kinds of entropies for Bakers transformation are presented. The Kolmogorov entropy of Bakers transformation is sensitive to the initial flips by the time. The topological entropy of Bakers transformation is found to be log k. The conditions for the state of Bakers transformation to be forbidden are also derived. The relations among the Shanonn, Kolmogorov, topological and Boltzmann entropies are discussed in details.