Abstract: This paper discusses the advantage and disadvantage of classical grey incidence decision-making.Firstly,it introduces a method based on ideal project for maximum grey incidence degree;a method based on critical project for minimum grey incidence degree,and integrated incidence degree method together with some relational concepts based on both ideal and critical projects,which consists of incidence degree coefficient formula and relative incidence degree coefficient formula for interval grey numbers.Secondly,three types of incidence degree decision-making arithmetic mentioned above are put forward.Then,it points out that incidence degree coefficient formula for interval grey number and maximum incidence degree method are generalizations of classic incidence degree coefficient formula and grey incidence decision-making,respectively,while methods for minimum grey incidence degree and integrated incidence degree are generalizations of method for grey incidence decision-making.Finally,an example shows the rationality of grey incidence decision-making and the validity of the arithmetic mentioned above.

Key words: grey system theory, interval grey number, grey incidence degree, grey incidence coefficient, decision-making