A method using stochastic response surface method is presented. It solves wave equation with uncertain parameters in shallow water. Uncertain parameters of ocean environment are expressed with standard stochastic variables. And stochastic response of coherent sound field is expressed by Hermite multinomials. An approximate expression of coherent sound field is achieved with coefficients of stochastic muhinomial solved by probabilistic collocation method. It shows that the proposed method is more accurate and efficient than Monte Carlo method and field shifting method.