1. Faculty of Geosciences and Environmental Engineering, Southwest Jiaotong University, Chengdu 611756, China;
2. School of Resources and Environment, University of Electronic Science and Technology of China, Chengdu 611731, China

Kirchhoff beam migration is a simplified Gaussian beam migration, which omits the dynamic information and can calculate multi-arrival traveltime, so it is a high-precision and fast seismic imaging method. In the imaging process, extracting common image gathers can be used for velocity analysis, improving the accuracy of modeling and imaging quality. Compared with the conventional common image gathers extracting methods, the angle-domain common image gathers extracting method can avoid the artifacts caused by multi-arrival seismic waves. The authors present a new method of extracting common image gathers in angle-domain from Kirchhoff beam migration and verify the method by numerical calculations.