Abstract: On the basis of the analysis of the motivation and the principle of metasynthesis from qualitative to quantitative, the relationship between metasynthesis and decision making is discussed, and the research of metasynthesis is supposed to be beyond the limit of decision making and decision making systems However, it should be regarded and utilized as a new methodology of science innovation In terms of so many complex key decision making problems, an approach to a metasynthetic decision making system is proposed based on the theory of metasynthetic engineering