Abstract: In order to satisfy the research of the deuterium and tritium retention in plasma facing components of fusion reactor, a nuclear reaction analysis system was designed and installed based on the original beam line of 4.5 MV electrostatic accelerator at Peking University. With this nuclear reaction analysis system, H⁺, D⁺, ³He⁺ and ⁴He⁺ beams can be provided in the ion energy range from 0.8 MeV to 3.6 MeV. The differential cross section of the nuclear reaction and the depth distribution of the element concentration in samples can be achieved by this system. The principle of nuclear reaction analysis, the equipment layout and the experiment method were discussed, and the data analysis results of D(³He,p)⁴He nuclear reaction were shown as application examples of this system. In addition, the depth resolution of less than 1.5 μm and the experimental error of 7.5% were achieved with this system.