This paper is concerned with new method to find the fuzzy optimal solution of fully fuzzy bi-level non-linear
(quadratic) programming (FFBLQP) problems where all the coefficients and decision variables of both
objective functions and the constraints are triangular fuzzy numbers (TFNs). A new method is based on
decomposed the given problem into bi-level problem with three crisp quadratic objective functions and
bounded variables constraints. In order to often a fuzzy optimal solution of the FFBLQP problems, the
concept of tolerance membership function is used to develop a fuzzy max-min decision model for generating
satisfactory fuzzy solution for FFBLQP problems in which the upper-level decision maker (ULDM)
specifies his/her objective functions and decisions with possible tolerances which are described by
membership functions of fuzzy set theory. Then, the lower-level decision maker (LLDM) uses this
preference information for ULDM and solves his/her problem subject to the ULDMs
restrictions. Finally,
the decomposed method is illustrated by numerical example.