Abstract: To address the challenges such as lower corrosion rate of acidizing fluid, complicated temporary plugging technique, and high operation cost in traditional acidizing treatment in inefficient wells with low yield in heterogeneous reservoirs in Liaohe Oilfield, a synergistic diverting acidizing technology incorporating polymeric organic composite acid with dissoluble diverting particles has been developed. This technology selects a polymeric organic acid with high rock matrix corrosion rate as the main agent, which is duplicated with mixed benzene, alcohol ether additives, and surfactants to form a composite acid fluid system characterized by the functions integrating efficient oil washing, emulsification carrying capacity, and dissolution and pore expansion capabilities. Combined with naturally selective temporary plugging formed by high-strength dissoluble diverting particles at the pore throat, the dynamic coupling of chemical dissolution and physical temporary plugging is enabled, thus, allowing orderly acid diversion and uniform acid distribution in deep heterogeneous reservoir. Laboratory experiments show that the polymeric organic composite acid achieves a dissolution rate of over 20% on artificial oil-based core particles, and a corrosion rate of 1.61 g/(m² ·h) on P110 steel coupons. The dissolution time of diverting particles ranges from 6 to 24 hours, with dissolving rate accelerating as temperature rises. The plugging capacity on cores is greater than 97%, with permeability recovery rate exceeding 95%, which demonstrates sound temporary plugging reversibility. This technology has been applied in 56 wells, with treatment availability of 92.8% and cumulative oil increment of 2.15×10⁴ t, achieving favorable application results. This research offers high-efficiency and low-cost diverting acidizing solution for the treatment of low-yield wells in similar heterogeneous sandstone reservoirs.