Abstract: The measurement of plutonium nuclear data is very important in the field of nuclear science. In order to obtain the relevant nuclear data of plutonium, it is necessary to prepare plutonium target and irradiate it in accelerator or reactor. According to the measurement requirements, plutonium targets with a diameter of less than or equal to 5 mm should be prepared, which should contain 4 μg plutonium at least. In this paper, a lot of experimental work has been done on the preparation of small area Pu target.  The electrodeposition system with sodium sulfate as the electrodeposition solution was determined through the study of three different electrodeposition systems, i.e. isopropanol, ammonium sulfate and sodium sulfate. The device was improved and the relevant process conditions were studied, and the preparation process of Pu target was determined. The electrodeposition was carried out at a current density of 750 mA/cm² at 65 ℃ for 150 min with sodium sulfate solution of pH=2.0-3.0. The electrodeposition percentage was detected by liquid scintillation spectrometer. The results show that the electrodeposition percentage of Pu is more than 98% with this method.