Abstract: To solve the problems of the generation and storage for 3-D prestack angle gathers, based on the idea of local harmonic decomposition, the 2-D angle gathers generation technology was extended to 3-D. The principles of this method are as follows. The expressions for incident wave and scattered wave in angle domain are presented through defining local angle transform and filtering factors in wave-number domain and spatial domain. Utilizing the trigonometric expansion coefficients of angle gathers for up- and down-going waves, together with relevant imaging conditions, the trigonometric expansion coefficients cube of reflectivity angle gathers is generated. Furthermore, with exponential mapping, reflectivity angle gathers are obtained. When coding the program, the research result of object-oriented large-step wavefield extrapolation is also resorted to realize the high efficient, accurate and target-aimed imaging. Meanwhile, the trigonometric expansion coefficients of harmonic decomposition are calculated in angle domain. The program adopts shot domain parallel scheme where the computation for host-node and that for servant-nodes are separated so as to free servant-nodes from saving angle gathers in middle procedures. Thus, the main duty for servant-nodes is to compute trigonometric expansion coefficients, while that for host-node is to reclaim them and generate a coefficients cube. Then, according to specific demands for target profile or cube, corresponding angle gathers are formed. Thanks to the schemes above, rather less disk space is enough for generating angle gathers. So, the problems of computing efficiency and storage are solved. The result of test, with 3D seismic data from an oilfield in Eastern China, shows that this method is feasible and practical.