AbstractThin‐walled polystyrene (PS) spheres are needed for preparing the targets in the inertial confined fusion (ICF). To prevent the occurrence of craze and crack in the fabrication of the spheres, a noncovalent interaction route is developed to improve the mechanical properties of thin‐walled polystyrene spheres based on a fullerene derivative, reducing the craze and crack yield. The introduction of phenyl‐C61‐butyric acid methyl ester (PCBM) into PS spheres not only improves the thermal stability, but also reduces the craze and crack yield, probably to the π–π interaction between PCBM and PS and the hydrophobicity of PCBM. The sphericity and surface finishing of the spheres also increase at the same time. Mechanism of how the PCBM improve the quality of the spheres is also discussed.Highlights A noncovalent interaction route to improve properties of PS spheres is proposed. PS/PCBM spheres with good quality are successfully designed and fabricated. Mechanisms of how the PCBM improve properties of PS spheres are also discussed.