Abstract: A fuzzy mathematical approach is proposed for bi-level programming problems in which the upper-level has constraints and the lower-level consists ofNindependent programming units. A bi-level programming problem is divided into many classical ones, then by introducing the concepts of membership functions, the solution of each classical programming problem is discussed with three theorems. Consequently, the bi-level programming problem can be transformed into solving a classical linear programming problem, enabling the problem being simplified.