In this paper, a three-stage ray optics (RO)-based modeling approach is proposed to characterize the maritime evaporation duct channel. The channel model follows the classic form which is a superposition of multipath components (MPC), while each MPC corresponds to an arrived ray identified by the RO method. We propose an algorithm to search for all feasible rays, with which important statistical channel parameters, such as the number of rays, reflection times, trajectory lengths, angles of departure/arrival, can be efficiently obtained. The proposed channel model is validated by comparing with the conventional parabolic equation-based approach. Large- and small-scale fad- ing characteristics of the duct channel are also analyzed and discussed based on the proposed model.