We develop an efficient scheme of illumination analysis along a target horizon. With this scheme, we can calculate the Directional Illumination (DI) from the sources and the Acquisition Dip Response (ADR) along a target horizon in very short turnaround time. Therefore, it can be a useful tool to study the influence of the model (e.g. salt body) and the acquisition system (e.g. shot distribution and aperture size). The result can be a guide for acquisition design and model building. With the illumination map along the target horizon, it also is helpful for the interpretation in areas where the image amplitudes are not reliable. Here, we use the wave-equation based migration and local plane wave decomposition method to get the frequency domain illumination in the local angle domain. We pre-calculated and saved the angle domain Green’s function along the target horizon. These Green’s functions are reusable so that we can save a lot of computational and I/O cost. We use the 3D SEG/EAGE salt model and a real model example to demonstrate the validity of our method.