A multi-eigenpath channel model is proposed to simulate the microwave transhorizon communication signal in marine atmospheric duct environment. The channel model identifies the relation between multiperiodical delay components and subeigenpath components. The simplified algorithm of subeigen signal is proposed on the basis on signal-to-multipath ratio. The application procedure of this model is described. The bit error rate of binary phase shift keying moduted signal in atmospheric duct is simulated by multi-eigenpath channel model.