Abstarct: The fuzzy set theory has been applied in many fields, such as operations research, control theory, and management sciences, etc. In particular, an application of this theory in decision making problems is linear programming problems with fuzzy numbers. The modeling and solving the optimization problem is one of the most important daily problem. By notation the nature of data in practice which are imprecise, fully fuzzy linear programming problem (FFLP) is a power full tool to modeling the practical optimization problem. This thesis investigates some methods for solving fully fizzy optimization problems. One of the methods of solving these problems, is lexicography method and fuzzy approximate solution .By using the concept of the symmetric triangular fuzzy number an approach to defuzzifiy a general fuzzy quantity is presented .So, a new method has been considered to find the fuzzy optimal solution of FFLP problems with equality constraints .Also, another method has been proposed for solving fully fuzzy linear programming with flexible constraints baxsed on a new order relation. In this method, three algorithms are developed to deal with FFLP problems by converting them into some equivalent crisp linear programming prbolems Next, another method is considered which is a simplified novel technique for solving Fully Fuzzy linear programming problems.