Like buildings with other types of foundations, buildings with pile foundations can tilt because of irrational designs, imperfections of foundation treatment, poor construction qualities, even the change of water environment during usage, etc. By studying and analyzing the causes for the inclination, this paper has proposed a theory of rectification and reinforcement for buildings with pile foundations based on the principle of counterforce center, which makes building be rectified by changing the counterforce center of pile foundation so that it can be in the same vertical line with the gravity center of upper structure. Then the calculation method was given. Combining with an engineering project, it has been proved that the principle of counterforce center is a good guidance for the rectification and reinforcement for buildings with pile foundations.