Abstract: In order to obtain an accurate and efficient algorithm for calculating statistical characteristics of the stochastic sound field in a random ocean media,we applied the polynomial chaos expansion into the wide-angle split-step parabolic equation model(RAM model)and developed a polynomial intrusive acoustic calculation algorithm.Thus,the calculation results of this algorithm are more accurate than these of narrow-angle parabolic equations embedded with polynomial chaos.And time cost is substantially reduced compared to the benchmark Monte Carlo method.In the simulation cases,the same accuracy with the Monte Carlo method as for calculating the first and second moments of sound intensity is available.While under the same computing conditions,the polynomial chaos expansion method will improve the calculation efficiency by at least 1 order of magnitude when the polynomials have limited arguments and maximal truncated powers.