Abstract: A novel ABC-type pH-responsive fluorinated triphilic block copolymer PMAA₃₀-b-PEHMA₅₁-b-PFA₆ was synthesized by three-step successive reversible addition fragmentation chain transfer (RAFT) polymerization and one-step acidolysis reaction, incorporating with methylmethacrylate (MAA), 2-ethylhexyl methacrylate (EHMA), and 1H,1H,2H,2H-perfluorodecyl acrylate (FA) as hydrophilic, lipophilic, and fluorophilic units, respectively. The internal structure of the as-prepared triphilic block copolymer was characterized by nuclear magnetic resonance hydrogen spectrum (¹H-NMR), infrared spectrum (IR), gel permeation chromatography (GPC) and fluoroelement analysis (F-EA). Otherwise, the self-assembly behaviors of the copolymer PMAA₃₀-b-PEHMA₅₁-b-PFA₆ in dimethylformamide/water (DMF/H₂O) solution were investigated by the turbidity measurement (OD), transmission electron microscope (TEM) and dynamic light scattering (DLS). The results indicated that the triphilic block copolymer exhibited an interesting morphology evolution from rod-like structure to the larger size tree-branch structure, along with water volume fraction increasing from 20% to 60%. The morphology formation mechanism was explained according to the comprehensive effect of multiple forces including that the crystallization of the side chains of the fluorinated blocks, the strong incompatibility between the lipophilic and fluorophilic blocks, the balance between the core-chain stretching and the shell-chain tension. Furthermore, the morphology transitions from rod-like micelles to multi-compartment spherical structures or to core-shell-corona spheres, as well as the corresponding changes of the diameters of the micelles, were obtained by adding acid (HCl) or alkali (NaOH) into the system. The micellar structure transformation was derived from the effect of protonation or deprotonation effect of the carboxyl, which was based on the ionization equilibrium of weak-acid PMAA polyelectrolyte in aqueous solution. This study amplified the self-assemble behavior of linear triphilic block copolymers, and contributed to the design of functional fluoropolymer.