Multi-granulation three-way decisions utilizes three-way decision theory to analyze and process complex problems from multiple of views and levels， gradually becoming an efficient and reliable intelligent decision-making method. This paper reviews the research work on multi-granulation three-way decisions， mainly introduces multi-granulation fusion strategy， multiview three-way decisions， and multilevel three-way decisions， discusses multi-granulation three-way decisions from both qualitative and quantitative perspectives， illustrates the relationships between different multi-granulation three-way decisions models， and points out several problems for the existing multi-granulation three-way decisions. The obtained results can provide some references for the deep research in this field.