The calculation formula of bearing capacity of local compression for masonry under pad-stone length larger than πho was given in the design code of masonry structures only, but with no counting formula if the pad-stone length is not larger than πho, when the local compression for masonry under pad-stone are taken into consideration . Therefore, this paper associates with elasticity theory and the calculation method of beam on elastic foundation to analyse the stress of the different length of pad-stone, then the different effective hight of pad-stone according to the different length of pad-stone are found, and ultimately obtain the different formulas for calculating the bearing capacity. The conclusions not only validate the calculation formula for pad-stone length larger than πho in the design code of masonry structures, but also give the calculation formula for pad-stone length not larger than πho ,which substantiate the code, and provide the necessary basis for masonry structure design.