本文討論解 Poisson's equation 的數值解在有界的定義域上,透過隨機漫步的方法,造出一種新的預處理 (precondition) 並且使用圖形處理器來加速此方程的數值解,而疊代法使用 Conjugate Gradient 方法並與現有的預處理方法做比較的有 ILU0,multigrid 在 CPU 上,其它還有對此新的預理討論收斂速度,以及給出一些改良策略。 This paper discuss to solve numerical solution of Poisson's equation on finite domain and create a new precondition with random walk method and use graphic process unit to accelerate numerical solution of this equation. At iteration method is used by Conjugate Gradient method and compare with ILU0 and Multigrid method on CPU, other discuss this new precondition has convergence rate and give some improvement strategy.