Grey Graphical Evaluation Review Technique Network and Its Estimation Precision of Grey Numbers Based on Clients

In this paper,Grey Graphical Evaluation Review Technique(GERT in brief) Network is put forward and its model is built up,for that the method of GERT Network requires accurate parameters of action,and however,people usually can not find out exact value of parameters because of limited information of real life.By Grey GERT Network,many actions are easier to be described and discussed.This paper defines several types of Grey GERT Network and searches for the approach to solution.And the estimating precision is advanced to measure the uncertainty of estimation on the condition that the degree of greyness can not be calculated.Two examples are also given to show the practical meaning.