AbstractCrosslinked polymers are considered to be promising materials for supporting catalysts that are effectively applied in different reactions. However, the application of polymer‐supported catalysts in high‐temperature processes is limited by their temperature stability. Besides thermal degradation, temperature changes can cause the restructuring of the polymer network because of changes in the valence angles and bond lengths. Thus, the study of the influence of temperature on the structure of crosslinked styrene–divinylbenzene (StDVB) copolymers is an important task. In this work, for the first time, the temperature effect limitations on StDVB copolymers are studied and justified. The changes in the polymer structure tension as well as in the specific surface area are studied using molecular dynamics simulation in the temperature range 77–723 K. Near‐cryogenic temperatures are not found to affect significantly the specific surface area. The heating of the polymer up to the temperature used for the reduction of catalysts (573 K) is shown to decrease the specific surface area by 11% because of an increase in the bond tension and valence angle deformation. Further increase in temperature leads to polymer decomposition. The results obtained can be considered for taking into account when applying polymer‐supported catalysts. © 2024 Society of Chemical Industry.