A scheme of convolutional perfectly matched layer (CPML) absorbing boundary condition (ABC) is proposed, which is used to truncate finite-difference time-domain (FDTD) method modeling transient electromagnetic (TEM) response. It derives specially CPML formulation dealing explicitly with divergence of magnetic induction and conceives an algorithm calculating convolutional term of z component. Then, the scheme is validated by numerical modeling of a homogeneous half-space model. The results indicate that efficient calculation of TEM is achieved.