The transport properties of step barrier on the surface of topological insulator are studied using transfer matrix method. It is found that the height of the step barrier influences the transport properties. Klein tunneling appears on the surface of a topological insulator and the transmission probability is depended on the height of the step barrier. The conductances show resonant tunneling behavior as the Fermi energy varies, and the switching effect can be obtained in the conductances as the difference of the height of the step barrier varies. So the conductance can be controlled by adjusting the Fermi energy and the difference of height of the step barrier.