Existing glioma treatments face challenges in simultaneously combining radiotherapy and chemotherapy while achieving long-term, stable continuous irradiation at low doses. To address this clinical challenge, two types of radiochemotherapy integrated dual-cavity capsules, single-capsule dual-cavity, and dual-capsule dual-cavity, were designed in this research. We employed finite element simulation and the Monte Carlo method to conduct stress-deformation simulation and dose analysis on the structure and manufacturing materials of the capsules. Based on these simulations, the structure of the dual-cavity capsule was optimized through orthogonal tests to obtain optimal results for tumor radiation therapy. Dose analysis experiments revealed that the dual-capsule dual-cavity structure exhibited improved irradiation effects on the lesion while minimizing damage to surrounding tissues and organs compared to the single-capsule dual-cavity structure. Stress-deformation simulation indicated that using polyetheretherketone as the capsule material enabled higher central dose rates and reduced deformation. Furthermore, the material’s ease of processing and low-cost characteristics facilitated the development of personalized and precise treatment approaches. The proposed capsule structure realizes the integrated combination of internal radiotherapy and internal chemotherapy, establishing a new mode of long-term stable local high-dose and peripheral low-dose radiation therapy. This scheme offers a novel treatment plan and advanced technical reserve for the integrated treatment of intracranial glioma radiotherapy and chemotherapy.