Abstract: On the basis of boundary element theory, combined with Chebyshev spectral element method, acoustic scattering numerical computation was studied. The second order boundary element was used in the computation of acoustic scattering field.  Chebyshev-Gauss, a spectral collocation point method, was used to realize the whole process in which spectral point were dispersed. As a result, this method overcame some shortcomings of traditional ones such as the discontinuity of normal direction and normal derivative that appeared on the nodes of surface element. With the application of a combined Helmholtz integral equation formulation (CHIEF), numerical non-uniqueness was solved and the computational accuracy and efficiency would be improved. Therefore, the new method advantage such as fast computation and high accuracy are drawn through the comparison and analysis with the traditional method.