Abstract: Nowadays, the study on wet-spray shotcrete compactness focuses on concrete proportion optimization, whose main content are comparing specimen compactness byspraying samples or boring samples.However, research on compaction process of wet-spray shotcrete jet flow is ignored, and how to adjust compactness lacks of reasonable support.On the basis of full investigation of previous research results, this paper analyzed the technological characteristics of compaction process, summarized the key compaction behaviors, reviewed the research progress of each key behavior, and proposedfurther research direction.It was suggested that adjusting compactness need to take into account concrete material and wet-spray techniques, their coupling mechanism should be explored.During the mechanism study, the rheological performance of concrete and its rapid evolution process should be fully considered.Especially, the “super early age” rheological characteristics within 2 minutes after accelerator is added to concrete needmore attentions.