I84V mutation in HIV-1 protease (PR) has produced drug resistance on multiple inhibitors. Thermodynamic integration (TI), solvated interaction energy (SIE) and dynamic analysis were applied to comparatively probe drug-resistant mechanisms of I84V mutation toward four inhibitors. Dynamic analysis suggests that in the I84V mutants the flaps of PR are more flexible and domains near the flaps of PR and residues 84/84' also change obviously. Binding free energy predictions show I84V mutation mainly drive the decrease in van der Waals interactions of inhibitors with PR. This study is expected to provide theoretical helps for designs of potent inhibitors targeting HIV-1 protease. (C) 2018 Elsevier B.V. All rights reserved.