In this study, we improve the performance of the enhanced Craig-Bampton (ECB) method. The improved ECB method is derived by employing the algebraic substructuring and interface boundary reduction. Unlike for the original method, the residual substructural modes are compensated only for the reduced mass matrix, and this is the most attractive feature of the proposed method to reduce the computation time significantly. In addition, for effective implementation and computer memory management, we give a computer-aided formulation of the reduced mass, stiffness, and transformation matrices. Several large structural FE models are used to illustrate the significantly improved solution accuracy and computational efficiency of the improved method. (C) 2017 Elsevier Ltd. All rights reserved.