To improve the convergence ability of a wave-front sensorless adaptive optics (AO) algorithm using a general model-based approach, an AO system simulation model based on Zernike modes is established with a 127-elements deformable mirror (DM). Using peak Strehl ratio (Sr) and the proposed fast-steady-convergence percentage as evaluation criterion, good correction capability for static distorted wave-front is verified by analyzing the impact of different perturbation coefficient, the number of Zernike modes, and slope factor on correction effect and convergence speed under different turbulence intensity. The results show that when the perturbation coefficient is less than 0.01, the system can converge steadily and increasing the number of Zernike modes can ascend Sr of the convergence while it will sacrifice some convergence speed. A modified vector slope factor is put forward, and the system correction can be improved efficiently after the first iteration. For the large distorted wavefront has strong adaptability especially.