Abstract: The development of additive manufacturing (AM, 3D printing) has made it a key common technology for the patterned deposition and integrated manufacturing of electronic devices. In the process of solution-based printing, the mutual coupling of micro-nano flows, solvent evaporation, and crystallization serves as the universal theoretical foundation determining deposition morphology and final device performance. This article reviews two typical liquid-based 3D printing processes: inkjet printing (IJP) and meniscus-guided printing (MGP). Taking halide perovskite—a prominent representative of solution-processable functional materials—as a typical demand case, this work summarizes the research and progress of micro- and nanoscale fluid phenomena during the printing process. IJP is deconstructed into three stages: jetting, drying, and film formation, to analyze the influence mechanism of solid-liquid-gas interfacial flows on the processing window. For MGP, the scaling relationship between the evaporation-controlled regime and film thickness is summarized, and the fluid dynamic mechanisms of local enrichment within micro- and nanoscale confined menisci, as well as the morphology transformation from hollow to solid, are discussed. Finally, this review summarizes the universal influence laws of micro-nano flows in 3D printing on the crystallization kinetics and film quality of functional materials (such as perovskites), providing a theoretical basis for the high-quality manufacturing of precision optoelectronic and flexible electronic devices.