Hierarchical self-assembly of triblock terpolymers (TTPs) in dilute solution to form multicompartment micelles (MCMs) typically involves two main steps: self-assembly of TTPs chains into intermediate star-like micelles and further self-assembly of star-like micelles into MCMs. The former step, in theory, has two possible pathways: single-stage self-assembly or hierarchical self-assembly, which has not yet been fully revealed. Here, an amorphous linear A-b-C type TTP polystyrene-block-polybutadiene-block-poly(methyl methacrylate) (abbrev. PS-b-PB-b-PMMA or SBM) was used as a model molecule; solvent exchange strategy was employed to induce self-assembly of SBM in dilute solution. Dynamic light scattering (DLS), static light scattering (SLS), and auxiliary transmission electron microscope (TEM) were used for real-time and dynamic monitoring of the self-assembly process of SBM into star-like micelles and further self-assembly of star-like micelles into MCMs. The results revealed that the self-assembly pathway of SBM in dilute solution into star-like micelles was a direct single-stage self-assembly pathway from SBM chain clusters/networks to form star-like micelles, rather than a hierarchical self-assembly pathway involving intermediate states such as single-chain or multi-chain micelles. Additionally, the concentration of SBM dilute solution had no significant effect on this self-assembly pathway, and the self-assembly process reached dynamic equilibrium within 12 hours. The results provide valuable information for the thermodynamic and kinetic studies of the self-assembly process of multi-component block copolymers in dilute solution, and for applying light scattering technology to characterize polymer solutions.