In the hedgerow orchard of hills area,the orientation of row changes with the direction of slope and the crown span also changes with gradient to meet the requirement of sunshine.In this paper,the solar locations of different time are calculated by astronomical triangle formula in vernal and autumnal equinox of the 40°N area,and the shadow length of the tree body and its coefficient of shadow length are also calculated at the same time.The diagram of tie line at top of shadow is drawn based on the relationship between sun azimuth angle and the coefficient of the shadow length.Then the crown span in the condition of different grade on the ground can be obtained by using the diagram of tie line at top of shadow in two rows of hedges according to the two kinds of designed row direction.When the seedlings are in south-north rows on the south slope,the crown span is d=h·ctga·sinA·cosi;and when the row direction is between SN direction and 45°SE and the aspect between 0°E and 45°NE,the crown span is d=d₁-Δd =h·cosA₁·(tgt₂-tgt₁)/[1+tgi· ctgα₂· sin(A₂-A₁)]· cosφ.The example results show that the models are feasible.