Based on the experimental orientation relationship, first-principles density function theory calculations were performed to study the α/ω interface in titanium. With different surface termination and interface coordination types, a total of 24 possible atomistic interface models of the α{1-100}/ω{1-100} were constructed and calculated. Five interface structures were favored in energy and may co-present in titanium, and the average interface energy was predicted as 0.100 J/m₂ with including the misfit strain energy, and 0.029 J/m₂ without including the misfit strain energy, respectively. These results are helpful in supporting the future phase-field simulations and in clarifying the phase transformation mechanisms in titanium.