Abstract: Nano-sized neodymium oxide was prepared by direct precipitation method with neodymium nitrate and ammonium carbonate as raw materials.The influences of concentration of ammonium carbonate,calcinating time,and different kinds of additives on product particle size were discussed.The cluster in drying and calcining precursor process was successfully solved by adding active carbon and the optimal preparing conditions of nano-sized neodymium oxide were confirmed.Product was characterized by XRD,SEM,and TG-DTA.Results showed that neodymium oxide with particle size of 30 nm had been prepared under a certain condition and synthesized neodymium oxide belonged to hexagonal array.This mehtod was simple and it was convenient to operate.Neodymium oxide was used as catalyst to synthesize n-butyl acetate,reaction time was shorter,neodymium oxide could be reused,and yield of the esters reached 54%.