Abstract The shear strength of hot mix asphalt (HMA) was evaluated with a direct shear device in this research. The indirect unconfined compression test was adopted to calculate the cohesion and the angle of friction of HMA mixtures. The influence of asphalt content, loading rate, and testing temperature on the shear strength of HMA mixtures was also investigated. The shear resistance properties of asphalt mixtures were investigated by a direct shear device using five gradations (i.e., two intermediate-graded and three large-stone mixtures). The results show that the shear strength is highly related to rutting resistance of the HMA mixture at a high temperature. Testing parameters have great influences on the cohesion component and low influences on the angle of friction. The shear strength of asphalt mixtures has good correlations with the dynamic stability through wheel-tracking tests. The angle of friction is susceptible to the mixture gradations and their design methods. The well-interlocked gap-graded mixtures have greater friction angles than the continuously dense-graded mixtures.