Abstract: Expression comprising finite series of power function is applied to characterize shear force allocation along pile shaft.Based on displacement compatibility relation,pile body stress and strain equation and force equilibrium relationship in elasticity mechanics,the stiffness matrix which relates pile top force to pile top displacement is deduced.With the above stiffness matrix,the pile shear force along pile shaft and the pile tip stress allocation in long-short pile group can be analyzed.It does not involve the discretization of the soil or piles.The method follows the same analysis process and the content of stiffness matrix is just related to the number of piles for long-short pile group.Comparison with the results of Poulos's method,Chow's hybrid method and finite element method shows that the analysis method in paper is feasible and accurate.