The three-dimensional analytical model was built on L-shaped high-rise buildings with podium, adopts layered ground model to simulate subsoil, joint connection unit was introduced, a combined action analysis of upper-structure-piled raft foundation-ground was made on high-rise buildings that do not set up joint, the influence was discussed which of change of ground stiffness on upper structure and piled raft foundation. It is indicated in the research that axial force of side and corner pillars, that are separately located in flange and central area of upper structure, decreases, while axial force of central pillar increases and tends to be uncombined action under vertical load when ground stiffness increases. Average settlement of main building and podium foundation decreases with the increase of ground stiffness. But this influence declines when ground stiffness increases to a certain degree. Settlement difference of main building and podiums decreases slowly with the increase of ground stiffness. With the increase of ground stiffness, reaction curve of top of pillar tends to be slowly, meaning that reaction of top of pillar is gradually well-distributed.