This paper presents a macro-model, which can be used to calculate the lightning-induced overvoltages (LIOVs) on overhead lines on MATLAB/Simulink platform. First, a macro-model according to Agrawal's field-to-line coupling model is derived, in which the distributed equivalent voltage sources due to the horizontal components of the incident electric fields are lumped at the terminals of the transmission lines. In order to interface with MATLAB/Simulink, the propagation function of the transmission line is approximated by a delayed rational function and described by a state-space representation, and Brune's synthesis is adopted to model the equivalent multiport equivalent circuit of the transmission line in order to overcome the passivity violation problem. Combining with the built-in components in MATLAB/Simulink, the proposed modeling approach is applied to evaluate LIOVs of an overhead lines system, and the influence of the arrester and ground wire on the LIOVs is discussed in this paper. Furthermore, considering that the peak values of LIOVs are mainly concerned in the insulation coordination, a simple model for the early time response is proposed, which can further simplify the procedure. The accuracy of the proposed modeling method is validated by some examples.