<p>Failure criteria of rocks form a fundamental theoretical basis for understanding rock deformation and failure mechanisms. The Hoek–Brown (H–B) criterion is extensively used in rock mechanics due to its simplicity and effectiveness in characterizing the macroscopic failure of rocks. However, it is insufficient to describe the multiscale mechanical behaviors of rocks, which are essential for comprehending complex failure mechanisms in tunnel surrounding rock. In this study, the traditional two-dimensional H–B criterion, termed the macroscale failure criterion, was improved by incorporating the coefficient of intermediate lateral pressure (<i>k</i>₀). Meanwhile, a mesoscale strength criterion was proposed based on the improved H–B criterion and the strain field measured using digital image correlation (DIC) in biaxial compression experiments. The applicability and discrepancies between the macroscale and mesoscale strength criteria were examined in characterizing the mechanical properties and failure behaviors of thin plate specimens through secondary development of FLAC3D. The results indicate that both criteria accurately reproduce the failure modes of specimens observed in experiments. However, the macroscale strength criterion tends to overestimate the strength of specimens, whereas the mesoscale strength criterion provides results consistent with experimental data. The mesoscale strength criterion exhibits a significant advantage in assessing localized rock failure and holds great potential for practical applications.</p>