The robustness and stability of self-assembled colloidal suprastructures are pivotal and challenging in the field of soft condensed matter and nanotechnology. Herein, we develop a novel approach to “self-locking” the colloidal suprastructures to achieve excellent stability by taking advantage of the topology of polymer brushes on nanoparticles. Compared to linear polymer brushes, looped polymer brushes can significantly improve the structural stability of the suprastructures. A combination of experiments and simulations reveals that the suprastructures achieve their significant stabilities through a “self-locking” mechanism by forming folded entanglement between looped polymer molecules. The stabilized suprastructures can stay intact in various organic solvent environments or under heating and mechanical oscillations. Furthermore, the interparticle spacing of suprastructures can be modulated by controlling polymer conformations in an aqueous solution through varying salt concentrations. This new approach of “self-locking” provides an easy-to-operate strategy to stabilize suprastructures and modulate interparticle distances without adding chemicals, which allows the potentially wide applications of colloidal suprastructures under harsh environments.