Understanding the direct interaction of nanostructures per se with biological systems is important for biomedical applications. However, whether nanostructures regulate biological systems by targeting specific cellular proteins remains largely unknown. In the present work, self‐assembling nanomicelles are constructed using small‐molecule oleanolic acid (OA) as a molecular template. Unexpectedly, without modifications by functional ligands, OA nanomicelles significantly activate cellular proteasome function by directly binding to 20S proteasome subunit alpha 6 (PSMA6). Mechanism study reveals that OA nanomicelles interact with PSMA6 to dynamically modulate its N‐terminal domain conformation change, thereby controlling the entry of proteins into 20S proteasome. Subsequently, OA nanomicelles accelerate the degradation of several crucial proteins, thus potently driving cancer cell pyroptosis. For translational medicine, OA nanomicelles exhibit a significant anticancer potential in tumor‐bearing mouse models and stimulate immune cell infiltration. Collectively, this proof‐of‐concept study advances the mechanical understanding of nanostructure‐guided biological effects via their inherent capacity to activate proteasome. Self‐assembling nanomicelles constructed by small‐molecule oleanolic acid (OA) significantly activate cellular proteasome function by directly binding to 20S proteasome subunit alpha 6 (PSMA6). Mechanistically, OA nanomicelles interact with PSMA6 to dynamically modulate its N‐terminal domain conformation change, thereby controlling the entry of proteins into 20S proteasome, thus accelerating the degradation of several crucial proteins and driving cancer cell pyroptosis.