Abstract: An increasing amount of papers described different ways to obtain the ideal scheme by grey target decision model but seldomly set out the relative benefits of each approach so that the choice of the approach seems arbitrary. Therefore, this study discusses various grey target decision techniques and guides researchers in choosing suitable techniques for different decision models. This paper reviews the literature about grey target decisions published from 2010 to 2020, particularly methodological innovation. These techniques are categorized by the five aspects of developing a grey target decision model: (i) main types of data, (ii) manipulation of data, (iii) determination of criteria weights, (iv) calculation of bull’s-eye-distance, and (v) hybrid models. These techniques are discussed in terms of their underlying principles, complexity, strengths, and weakness. Summary tables and specification charts are given to guide the selection of suitable techniques. 

Key words: Grey System Theory, Grey Target Decision, Review