This book proposes an interactive approach to find the optimal fuzzy solution of fully fuzzy multi-level linear programming (FFMLLP) problem. Firstly, convert the problem under consideration into non-fuzzy multi-level multi-objective linear programming (MLMOLP) problem by using the bound and decomposition method. Secondly, simplify the MLMOLP problem by transforming it into separate multi-objective decision-making problems with hierarchical structure, and solving it by using -constraint method. The main results obtained in this book will be explained by an illustrative numerical example.