At present, there are technical problems in the development of water injection in horizontal wells in ultra-low permeability chang 6 reservoirs, the applicable conditions for water injection development, the unclear adaptability of volume fracturing parameters and reservoir geological conditions, and the lack of reference cases for well pattern combination and production technology policy, which make it impossible to promote the sustainable development of efficient water injection development of horizontal wells in the oilfield. In this paper, the LGR Local Grid Refinement method is used to deal with the segmented multi-cluster fracturing fractures of horizontal wells, and the oil-water two-phase black oil model and streamline model are established for horizontal well development in Chang 6 ultra-low permeability reservoir. With the help of the orthogonal design method, the injection-production and energy replenishment methods of horizontal wells were systematically optimized, the optimal well pattern form, fracture parameters and injection-production parameters were determined, and the productivity sensitivity analysis of horizontal wells was carried out, and the seepage law of the optimal injection-production combination scheme of horizontal wells was revealed. On this basis, the optimal development method of radial horizontal well pattern in the study area was optimized. The results show that for the consistent injection amount of different schemes, the production dynamic index of the well group is predicted by the digital model, and the influence of the recovery degree and water cut increase during the prediction period is comprehensively considered, the recovery degree under the same water cut of the staggered well pattern scheme is higher, and the recovery degree of water flooding with smaller discharge distance is higher, and finally the optimal discharge distance, well pattern and injection-production parameter data are obtained. Finally, a set of technical policies for the development of injection-production and energy replenishment in horizontal wells suitable for Chang 6 ultra-low permeability reservoir in the study area were obtained, and the relevant research results can provide theoretical basis and practical guidance for the efficient development of similar ultra-low permeability reservoirs.