Abstract: With process optimization requirements and technological progress, ultra-fine iron fine powder is increasingly widely used in sintering production, but its specific impact on sintering indicators is not clear. This paper aims to explore the impact mechanism of ultra-fine iron fine powder on sintering production indicators and the reasons for its negative impact. In this paper, through laboratory equipment and sintering cup experiments, the ultra-fine iron fine powder was comprehensively analyzed from three aspects of physical and chemical basic characteristics, granulation performance and quasi-particle burst. And the sintering cup experiment was used to verify and reveal the comprehensive influence mechanism of ultra-fine iron fine powder in sintering production. The experimental results show that the particle size of ultrafine iron fine powder B is only 14.1 μm, but the basic characteristics of high temperature and granulation performance are better than the general iron fine powder A. The assimilation temperature is 1 278 ℃, and the drying fines removal rate is only 10.10%. But through the heat burst experiment of quasi-particles, it is found that its strong water holding capacity is the main reason affecting the sintering production index. By reducing the water content of ultrafine iron fine powder B, the negative effect of water holding on sintering process was weakened, and the economic and technical indexes of sintering were significantly improved.