Abstract: Within the framework of the Heston model, this paper derives the recursive valuation formula for guaranteed minimum accumulation benefit (GMAB) products using a backward recursion approach. To simplify the integral form of the unknown functions in the recursive formula, the Gaussian-J integration technique is employed. Additionally, the frame duality projection (PROJ) algorithm is utilized to approximate the conditional density function of the logarithmic asset price, leading to the numerical calculation formula for GMAB products. Numerical experiments demonstrate that the PROJ algorithm effectively values GMAB products under the Heston model and explores the impact of model parameters on the valuation results.