Abstract: The successful implementation of the boundary element method depends on the efficiency and accuracy of solving the boundary integral equation. Accurate evaluation of singular domain integrals is crucial for achieving reliable numerical results. In the BEM implementation, an adaptive element subdivision method based on affine transformations is proposed for computing singular domain integrals. The proposed method employs affine transformations to partition the element into a projection region and subdivision regions. A radial projection algorithm is utilized to construct high-quality integration sub-elements between the source point and the projection region. Concurrently, adaptive subdivision is performed on the subdivision regions, generating regularly-shaped sub-elements with a density graded from dense to sparse. By performing the element subdivision algorithm separately for different regions, singular domain integrals in various elements and at arbitrary source point locations are effectively handled. This ensures computational accuracy while avoiding redundant calculations caused by excessive integration points. Numerical examples validate the accuracy, convergence and applicability of the proposed method.