As one of the critical target of lithographic lens, pupil non-balance is modulated by many factors. It is necessary to distinguish the respective contribution of those factors. In this paper, a method is introduced to calibrate pupil balance by removing telecentriciy, and a comparison is made with another approach based on finding centroid. A user defined program, which is written in Matlab with the function of manipulating Code V and LightTools data, is consequently made up to implement the above technique and calculate the real position of pupil intensity in angular plane without telecentircity. Beside, a series of simulation on an optimally designed lithographic lens under off-axis illumination is given to show the verification. It is revealed that this method is functional in calibrating pupil non-balance with a high level of implement efficiency.