Abstract: Aiming at the problem that the epistemic uncertain parameters exist in a acoustic field, an evidence theory- based finite element method (ETFEM) is proposed by introducing the evidence theory, in which the focal element and basic probability assignment (BPA) are used to describe the epistemic uncertainty. In order to alleviate the computational cost, the interval analysis technique based on perturbation method is adopted to acquire the approximate frequency response amplitude bounds for each focal element. The corresponding formulations of intervals of expectation and standard deviation of the approximate frequency response amplitude with epistemic uncertainty are deduced. The sound pressure response of a 2D acoustic tube and a 2D car acoustic cavity with epistemic uncertain parameters are analyzed by the proposed method. The proposed method is verified through the comparison of the analysis results of random acoustic field with that of epistemic uncertain acoustic field in which the epistemic uncertain parameters are obtained by discretizing the random parameters. Thus, the proposed method can analyze the 2D acoustic field with epistemic uncertainty effectively and provide a reliable model for noise prediction, which has good prospects of engineering application.