Highrise Frame-Core Composite Structures (HFCCSs) are commonly used in complex high-rise public buildings due to their high structural stability. Designing these structures while simultaneously considering economics and rationalization remains a challenge, as the existing solution-validation-iteration design method is time-consuming and labor-intensive. To address this issue, an automatic optimization method for HFCCSs is proposed based on a modified optimization heuristic algorithm. A 19-story, 68.7-m HFCCS was used as a case study to validate the effectiveness of the proposed optimization approach. Multi-objective optimization was performed to obtain more design insights of this structure, using material strength and cross-sectional dimensions of components as optimization variables, and the two material amounts as optimization objectives. The results show that a rational arrangement of structural components is obtained, while reducing material costs and ensuring that design parameters meet code requirements. This proposed approach can efficiently optimize HFCCSs, providing an effective tool for designing composite structures.