In order to study the phenomenon that the particles contained in the two⁃phase flow in the nuclear power plant are deposited in the pipeline under high temperature and high pressure, the mechanism of particle erosion on the pipeline is deeply explored. The similar principle and approximate modeling method are used to design and build a nuclear power pipeline. The experimental platform for the key parameters of the actual operation of the system.The results of the 30 h elbow deposition experiment show that the outer wall and inner wall of the 90° horizontal elbow are the sedimentary hot area, the outer wall axial angle of 30～45 degrees is the maximum sedimentary area, the maximum deposition of Co elements is 1.98×10－10 g on 8 mm×8 mm×3 mm sample. The results of this paper can provide data basis for radiation dose prediction and radiation protection of nuclear power plants.