Fmoc is usually used as an amino-protecting group. The traditional removal method is realized by using a secondary amine. However, this method has some shortcomings including high cost, difficult recycle of excess secondary amine and environmental pollution. The paper reports a novel heterogeneous deprotection method of Fmoc group using a new inorganic base, namely, nano-potassium carbonate. Nano-potassium carbonate with average particle size 64 nm is prepared using wet grinding method. The deprotection of Fmoc-Phe-OBn is preformed as a Model reaction. The optimum conditions are that reaction solvent is absolute ethanol, molar ratio of Fmoc-L-Phe-OBn to nano-K₂CO₃ is 1︰2, and reaction temperature is 25 ℃. The corresponding free amino compound is obtained with high yield. To further explore the scope and limitations of this method, seven substrates including Fmoc- anmino acids and dipeptides are examined. All the yields are above 98%. The nano-K₂CO₃ could be regenarated and reused for 5 times without loss of its reactive activity. This method has the advantages of simple operation, low cost, small pollution and recyclable potassium carbonate，and has important reference value for the research on the synthesis and deprotection of polypeptides.