A double-layeredmodel predictive control (MPC), which is composed of a steady-state target calculation (SSTC) layer and a dynamic control layer, is a prevailing hierarchical structure in industrial process control. Based on the reason analysis of the dynamic controller infeasibility, an on-line constraints softening strategy is given. At first, a series of regions of attraction (ROA) of the dynamic controller is calculated according to the softened constraints; then a minimal ROA containing the current state is chosen and the corresponding softened constraint is adopted by the dynamic controller. Note that, the above measures are performed on-line because the centers of the above ROA are the steady-state targets calculated at each instant. The effectiveness of the presented strategy is illustrated through two examples. (c) 2017 The Chemical Industry and Engineering Society of China, and Chemical Industry Press. All rights reserved.