High Ductility Concrete (HDC) exhibits unique mechanical properties at ambient temperatures, but its behavior at elevated temperatures is less understood. This study examines the mechanical behavior of Rubber-modified High-Strength High-Ductility Concrete (R-HSHDC) across various temperatures (25, 75, 100, and 150°C) and rubber replacement ratios. The study explores R-HSHDC’s microstructure, failure modes, strength, and deformability, focusing on its pseudo-strain hardening behavior. Results indicate that below 100°C, R-HSHDC displays typical HDC characteristics, including multiple cracking and high tensile deformation. As temperature increases, both initial cracking strength and tensile strength decrease, while crack control and energy absorption are maintained. Moderate rubber powder reduces initial cracking strength and enhances tensile deformability. When using R-HSHDC as a structural material, temperature effects must be considered. At higher temperatures, R-HSHDC is more suitable for crack control and energy dissipation. This research improves understanding of R-HSHDC's behavior at different temperatures, aiding in structural and functional design for high-temperature environments.