The correction algorithm is researched to solve non-uniformity of multiple channels output of area-scan CCD image. Various factors are analyzed contributing to the non-linear behavior of multiple output CCD. The method of multi-section linear approaching correction is proposed. The algorithm principle and its simple realization method are introduced in details. The correction algorithm is realized based on FPGA. Multi-section linear approaching correction algorithm has higher precision than two-point correction algorithm. It also has lower operation load than multi-point correction algorithm. This method satisfies the camera nonuniformity correction requirements

has very strong practicality.