Abstract: In the present paper a loading technique of colloidal graphite and urani-um sample have been described. The results show that the layer of TaC formsand the ionization of uranium are realized simultaneously in the system ofUO_2 (NO_3)_2, Ta and C. With the aid of this technipue the premature evapora-tion of uranium sample can be precluded and the stablity of ion current isimproved.