Abstract: In accordance with the requirement of ground communication system of remote distance for short wave band, on the basis of the model calculation of the mean background of ionospheric parameters, a method is presented for calculating the trace of short wave ray in ionosphere. The work is mainly concentrated on two aspects. First of all, bacause the frequency of short wave is relatively higher, the magnetic and collision effects in refractive index are neglected, so that general ray equations are simplified. In the second place, a method of calculatitng he first-order partial derivative of ionospheric plasma parameter is presented. The calculation of the partial derivative is on the basis of model result of parameters of each ionospheric layer, that is, on the basis of mean background of ionospheric parameters.It can be used in HFcommunication system, and other short wave system such as target position system of HFradar, etc.