Abstract: The routing of nitric acid, uranium, plutonium, technetium and zirconium in 1A unit of Purex process under different burnups and process conditions was researched by computer simulation, and the extraction behavior data of acid, zirconium, technetium, uranium and plutonium were obtained. Otherwise, distribution ratio curves of D_Tc(Zr), D_Zr andD_Tc were determined by experiments. Combining the computer simulation results and distribution ratio data determined, the extraction behavior of technetium was excused. In extraction process section, technetium is extracted into organic phase because of the co-extraction of zirconium and technetium, in washing process section, technetium remains in organic phase because of the co-extraction of technetium with uranium and plutonium. Compared with the influence of nitric acid on the extraction of technetium in washing process section, the co-extraction of technetium with uranium and plutonium is more important.