Abstract: A new type of multi-field collaborative processing technology that coupled phase change aggregation and turbulent aggregation was proposed to address the problem of low efficiency in the treatment of sintering flue gas ultrafine dust. By the numerical simulation methods, the aggregation behavior of sintering ultrafine dust under multi-field effects and the influence of its evolution parameters on aggregation efficiency were thoroughly investigated. The research results show that the lower inlet velocity can significantly improve the aggregation efficiency, as evidenced by a decrease in the average particle size of sintering ultrafine dust and an increase in the number density of large particle dust at the outlet. When the inlet velocity is 2.0 m·s⁻¹, the average particle size is 16.10 μm, and the number density of large particle dust at the outlet is 5.08 × 10⁴ particles per cm³. Although the increase in initial volume fraction is not conducive to dust growth, it is directly proportional to the number density of large particle dust at the outlet. When the volume fraction is 0.23%, the average particle size is the largest, as 19.80 μm, and when the volume fraction is 0.62%, the number density of large particle dust is the highest, reaching 7.40×10⁴ particles per cm³, indicating that a higher volume fraction is beneficial for dust treatment. An increase in the initial particle size of the dust can lead to a decrease in the final particle size density, which is inversely proportional to the number density of large particle dust at the outlet. When the initial particle size is 0.78 μm, the final particle size is the smallest, as 38.90 μm, but the outlet density is the highest, as 8.17×10⁴ particles per cm³, indicating that a smaller initial particle size is more conducive to the effectiveness of the collaborative processing technology.