The fluid dynamic behavior of halide perovskite precursor solutions during thin-film formation was systematically elucidated, and a unified theoretical framework for regulating solute transport, evaporation dynamics, and crystallization evolution was established. Rheological measurements, kinetic analysis, and numerical simulations of representative coating processes were combined to characterize velocity distributions and concentration migration during the stages of viscous flow, interfacial spreading, and evaporation-induced solidification. In addition, particle image velocimetry and interfacial tracking techniques enabled coordinated observation of flow-field structures, evaporation front positions, and crystal orientation. The results indicated that the solvent system, shear conditions, and interfacial properties were key variables governing solute distribution and crystallization pathways, and the appropriate control of evaporation gradients and interfacial energy could effectively suppress the coffee-ring effect. Overall, a systematic mechanistic framework spanning solution engineering, process control, interfacial regulation, and structural characterization was established, providing a predictable and designable pathway for achieving highly uniform, low-defect perovskite thin films and a theoretical basis for the controlled fabrication of solution-processed perovskite optoelectronic materials.