The inverted triangular boom is a structural form that is frequently adopted for large flat-top tower cranes. The upper chord members of each section of the boom are interconnected by pins, while the lower chord members are positioned by axial positioning shear pins. The luffing trolley travels along the lower flange of the lower chord of the boom. Under the effect of the wheel pressure, the lower chord will undergo bending. When the wheels’ act in the vicinity of the connection between the two boom sections, either one or both of the booms present a cantilever state, and the shear pins that interconnect them are in a sheared condition. Employ the theory of single-span cantilever beam and the theory of deformation compatibility The force conditions of the shear pin for axle box positioning between two beams in relation to the wheel pressure and wheel position were investigated. The linear superposition theory is used to study the effect of double wheels on shear pins. The influence coefficient of wheel spacing on pin shear is greater than that of wheel and pin position. Through the calculation in this paper, the force acting on any position and quantity of cantilever beam can be directly applied without complicated calculation, which provides a basis for the design of axial positioning shear pin.