Abstract: Flocculation flotation is the most efficient method for recovering fine-grained minerals, and its essence lies in flotation and recovery of flocs. Fundamental physical characteristics of flocs are mainly determined by their apparent particle size and structure (density and morphology). Substantial researches have been conducted regarding the effect of floc characteristics on particle settling and water treatment. However, the influence of floc characteristics on flotation has not been widely studied. Based on the floc formation and flocculation flotation, this study reviews the fundamental physical characteristics of flocs from the perspectives of floc particle size and structure, summarizing the interaction between floc particle size and structure. Moreover, it thoroughly discusses the effect of floc particle size and structure on floc floatability, further revealing the influence of floc characteristics on bubble collision and adhesion and elucidating the mechanisms of interaction between flocs and bubbles. Thus, it is observed that floc particle size is not the only factor influencing flocculation flotation. Within the appropriate apparent particle size range, flocs with a compact structure exhibit higher efficiency in bubble collision and adhesion during flotation, thereby resulting in enhanced flotation performance. This study aims to provide a reference for flocculation flotation, targeting the development of more efficient and refined flocculation flotation processes in the future.