This study builds on the practice of using waste rubber to improve the ductility of cement mortar and further explores the potential of vinyl acetate-ethylene (VAE) in enhancing the ductility of rubber cement mortar (RM). It systematically analyzes the effects of VAE on the workability, mechanical properties, crack resistance, and microstructure of RM. Additionally, isothermal calorimetry was employed to investigate the mechanism of VAE's influence on cement hydration heat. The results show that VAE significantly improves the flexural strength, tensile strength, and ultimate tensile strain of RM, while reducing its compressive strength and tensile elastic modulus, thereby markedly enhancing its flexibility and ductility. At a VAE content of 4%, the fluidity, 28-day flexural strength, tensile strength, and ultimate tensile strain of RM reached 240 mm, 4.83 MPa, 1.92 MPa, and 233 × 10