Abstract: Alternative iteration methods is improved dependence of initial value by introducing homotopy method，it becomes a large-scale convergence method，so algorithm’s generality and stability is improved，it can be applied to the practical engineering effectively.

Key words: homotopy method, alternative iteration method, double exponential fitting

摘要： 通过引进同伦法，改善了交替迭代法对初值的依赖性，使得大范围收敛成为可能，从而提高了算法的通用性和稳定性，可有效地应用于工程实际。

关键词: 同伦法, 交替迭代法, 双指数拟合