We have studied the Non-uniformity correction (NUC) algorithm for infrared image with large field of view(FOV).Firstly,we analyze the limitation of the global correction method for large FOV IR images, then we propose the idea of block processing for such images, and obtain the offset parameters to correct the non-uniformity. Finally, we simulate to prove this method can diminish the fixed-pattern noise in single frame situation. It can improve the non-uniformity of the images effectively.