Abstract: There are several ways to calculate the lateral pressure of squat silos.The most popular are Rankine and Coulomb earth pressure theories which are based on the consideration that the soil behind the retaining wall is two-dimensional plane.So they may not be suitable for a silo wall whose projection is circular on the plane.Furthermore,it is almost acceptable that the wall pressures vary linearly with depth according to the above two theories.Nonetheless,the bulk-solid pressure may not distribute linearly with depth because a bulk-solid behaves very differently from a fluid.The real pressure distribution law and calculation methods are studied.Based on the limits equivalent theory and through rigorous mathematical deduction,the curvilinear lateral pressure distribution is acquired.The results are in good agreement with that of the full-size silo experiment for both the horizontal plane top and the conical pile top of the stored bulk material,while Rankine's formula and Coulomb's formula are not accurate for the two cases.