Canal is seriously damaged from frost heave in seasonal frozen soil region. The mechanism of “frozen soil- lining structure” is complicated and highly non-linear, which limits the application of numerical calculation in the design and structure optimization of canal. A simplified algorithm of “frozen soil- lining structure”, which simulated the normal frost-heave force using “initial displacement method” and the contact friction effect by defining Mohr-Coulomb contact element, was proposed in this study. Whereafter, the mathematical model of canal structure optimization was established, and the finite element parametric model of canal was established based on the secondary development of APDL language. Lastly, the first order algorithm was used to optimize the structure in actual project. The results show that the algorithm is simple and practical, and the calculation results are consistent with the actual damage characteristics of the canal, and can be used in the calculation and design of the canal frost-heaving resistant structure. The optimized section does not crack and could assure the safe operation of canal under the worst meteorological and hydrological conditions. Meanwhile, this method can reduce the costs by 6.7% for section compared with the traditional designed section, making significant economic benefit for the whole irrigation area.