Abstract: Based on decision-theoretic rough sets and practical situation, the concept of three-way decisions is a kind of decision theory proposed by Yao et al. With the aid of this theory, the positive, negative and boundary regions of rough sets are given a new semantic explanation, which correspond to the notions of acceptance, rejection and deferment in decision making, respectively. Since the raise of three-way decisions, it has attracted many scholars’ attentions and it is improved and expanded to many fields. In this paper, we firstly introduce the background and basic theoretical models of the three-way decisions. Then, we can review the current research status and progress of this topic. Finally, we look forward to the future research trends.