An enteric formulation of duloxetine, its core and preparing method thereof are disclosed. The core comprises duloxetine or its salt and pharmaceutically acceptable excipients. The excipients include water-soluble hot melt materials selected from PEG, poloxamer, polyoxyl (40) stearate or their mixture. Based on the total weight of the core, the amount of water-soluble hot melt materials is 10%∼40% and the amount of duloxetine or its salt is 15∼60%. The core material is prepared by hot melt process. The enteric formulation comprises the core, a separating layer and an enteric layer.