Rankine theory and Coulomb theory are not suitable for the calculation of wall pressure by bulk materials, so this paper studies the actual distribution and calculation methods for the wall pressure in squat silos. Based on the limits equilibrium theory, the force on unit width of wall exerted by bulk materials is obtained, and the distribution of wall pressure is obtained by accurate mathematical deduction. It is proved that the results are in good agreement with those of the full-sized silo experiment, whether the top of the stored bulk materials is a horizontal plane or a conical pile.