In wireless network, terminals are usually energy constrained. In order to extend the lifetime of the terminal, the limited energy must be utilized in an efficient manner. In this paper, under the constant transmission power scenario, the authors propose an Energy Efficient Transmission Policy (EETP) which is derived by using Markov Decision Process (MDP). The simulation results show that compared with the Threshold Transmission Policy (TTP), the proposed policy can reduce the energy consumption significantly, while satisfying the performance demand at the same time.