Aimed at the evaluation problem of the missile defense engage schedule chain, in the description of the uncertain and fuzzy information flow parameter by three-parameter Vague value, the information superiority conversion evaluation V-GERT network model is established by the GERT network theory. The basic parameter calculation theorem of V-GERT network is also given. Then the information superiority conversion probability and conversion effect evaluation factor model are put forward. The probability and evaluation factor can be considered as an engage schedule chain measurement to provide a way for the design and optimization of missile defense engage schedule chain.