Soy glycinin amyloid fibrils (11Fs) with different lengths were prepare, and their influence on 3D printing performance of high internal phase emulsions (HIPEs) were investigated. The longest fibril with an average length of 1594.40 ± 135.56 nm and a maximum surface charge of 27.62 ± 0.57 mV was obtained after 9 h heating treatment. The intermolecular force analysis revealed that the formation of amyloid fibrils was mainly mediated by hydrophobic interaction. The interfacial rheology showed the fibrils had faster diffusion and rearrangement rate at the oil-water interface compared with 11S, leading to a quicker reduction in the interfacial tension. Notably, the interfacial film formed by 11F9 maintained the highest dilatational modulus, which might be attributed to the entanglement of long fibrils to form a more elastic and tough network structure, thereby enhancing the storage and thermal stability of HIPEs. With increasing fibril length, the viscosity, G' and G'' of HIPEs slightly increased, and the linear viscoelastic region (LVR) gradually widened. 3D printing test revealed that HIPEs formed of 11F9 had good extrudability, high printability and shape fidelity. This study could provide a promising guide for enhancing the 3D printing performance of protein-based HIPEs.