Through strictly proving the equivalence of the least squares method and Gram-Schimdt algorithm in fitting interference wave-front with Zernike polynomials, it is demonstrated that all algorithms of solving Zernike polynomial coefficients in the solving process are the same in stability. That is, when one of these algorithms is interrupted or a mutation appears in fitted interference wave-front in the solving process, then it is also not possible for the other algorithms to fit interference wave-front correctly. The research results show that no algorithm is superior to other algorithms in fitting the interference wave surface with Zernike polynomials. All these algorithms are equivalent in reliability except that their fitting processes are different.