Abstract: To study the deep rock strength, this paper proposes a five-parameter deviatoric function to modify the deviatoric function of the Hoek–Brown (HB) criterion, introduces an intelligent optimization algorithm (IOA) to determine the material parameters, thereby constructing a modified three-dimensional (3D) HB criterion. The proposed criterion avoids the defects of the HB criterion, which neither considers the Intermediate principal stress (IPS) nor meets the smoothness requirement, and overcomes the shortcomings of parameter determination based on conventional methods, which can lead to a single deviatoric plane envelope shape. This criterion can be degenerated into the HB criterion under triaxial compression and tension. The proposed criterion is verified using true triaxial test data for six types of intact rock, and the modified 3D HB criteria are selected for comparative study. The results show that the proposed criterion under the IOA has the best prediction error for the six rock types, ranging from 1.6636% to 3.4023%. Overall, the proposed criterion outperforms existing modified 3D HB criteria in prediction. Building on this, an intelligent prediction system was created to accurately predict deep rock strength. This system provides a new approach for intelligent prediction of deep rock strength and the dynamic construction of rock material parameters.