Abstract: To improve temporary plugging efficiency of reservoir rock with divergent distribution of larger pores,the temporary plugging method called "optimum filling for multi-stage pores" are presented in this paper.Based on the "interlayer packing" theory,continuous distribution of pore and bridging particles were discretely processed and matched to let reservoir pores be best filled,getting standard particle size distribution curve.The discrete process of continuous pore distribution was used to Qikou depression for selecting bridging particles in terms of distribution curve of particle sizes to get the best filling of multi-stage pores.The results showed that size distribution of calcium carbonate particles larger than 100-mesh was the best match of the standard size distribution curves.Reservoir protection experimental results indicated that drilling and completion fluid developed based on "best filling of multi-level pores" temporary plugging methods had good sealing performance,the pollution depth was less than 0.9 cm,and the rock permeability recovery rate was 97.29% after the polluting end being cut down.Field application results showed that the optimized particles can form a seal to prevent drilling and completion fluid from entering into formation,it can be concluded that temporary plugging method of "best filling of multi-stage pores" is suitable and effective for optimization of bridging particles for those pay zones with dispersed pores.