Fuzzy and grey are the double-characters of the information in supportability assessment and the fuzzy whitenization and grey incidence are effective methods used for solving the problems of data indefindbility and deficient data quantity in modern engineering realm. The new model called whitenization and grey incidence model in supportability assessment is initially presented in this paper. Based on whitening of qualitative indexes, the grey incidence analysis is executed. So, this paper has practical value in improving the accuracy of supportability assessment results and in enhancing the development of supportability assessment.