As traditional oil resources progressively diminish, elevating the recovery rate from mature oil fields has emerged as a pivotal concern within the petroleum sector. Among various advanced techniques, chemical flooding technology, particularly the application of branched preformed particle gel (B-PPG), has garnered significant interest. The B-PPG holds promise for its capacity to significantly augment oil recovery rates. Nonetheless, the efficacy of B-PPG is contingent upon a multitude of factors. These include the particle size, which must be optimized for interaction with reservoir formations, the concentration of the B-PPG, and the compatibility of the particles with the formation pore structure. Addressing these factors is essential to ensure the technology's performance and reliability in the field. We conducted laboratory experiments on oil-water two-phase flow to determine how various types and concentrations of gel particles influence oil displacement performance. The results revealed that B-PPG with varying types and concentrations exhibits four behaviors when passing through pores: straight through, aggregating, deforming, and plugging. High-concentration, small-particle B-PPG and low-concentration, medium-particle B-PPG optimize oil recovery and minimize residual oil saturation. The results of this study significantly enhance oil field displacement optimization. Selecting the appropriate type and concentration of gel particles can effectively boost oil field recovery rates, offering new strategies for their development.