Most of the existing methods are based on centriodal. Some methods are complicated such as [29].
Many conclusions of methods do not conform the objective facts such as [26],[27],[30]. In this paper, we have
ranked the generalized L − R fuzzy numbers based on the possibility theory and the implication of
possibilistic mean and possibilistic standard deviation. The method is simple to calculate and easy to use. We
illustrate not only the usefulness of the ranking method which is given, but also the defects of the existing
methods by compared with the given method. The article gives the ranking method of triangle fuzzy numbers
and trapezoid fuzzy numbers, which has an important value of innovation