Abstract: Actually, any engineering designs can be summed up for systematic optimizations. In real process, the traditional algorithm is always obtained by experience and needs massive computations and repetition. This paper attempts to apply the Immune Genetic Algorithm(IGA) to the transformation of the second irrigation channel of Yanghe River in Huailai, Hebei Province. Taking the second main channel in the irrigation area as the typical channel, the trapezoidal section parameters such as bottom width, designed stage, and so on were optimized. The IGA searching results show that IGA has less calculation, higher precision, more outcomes; solves the optimization problems more effectively and has higher application value.