Abstract: Relief is the essence of shade for sunshine.With the solar movement, the same relief can have a different influence on sunshine in different directions. According to this idea, this article discusses a computation about geographic sunshine hours based on direction nonidentity and takes 634 weather stations as an example to educe geographic sunshine hours empirical model about relief, which is [Hour_t=0.866·Rr + 131.3 ]. The result shows that the model has good fitting accuracy and the regression coefficient is 0.841. The correlation coefficient of geographic sunshine hours calculated by empirical and theoretical models is 0.953. The model needs only one parameter, relief degree, which is simple and easy to obtain. Weather station’s position is a fixed value, whose relief degree is also a constant within a certain range. And the relief degree can be used as an invariable geographical parameter for weather stations. So the model can be used widely in the future.

Key words: China, direction nonidentity relief degree, empirical model, geographic sunshine hours