Abstract: For the spent fuel generated by the operation of nuclear power plant, uranium, plutonium and other nuclides are extracted through the processes of shearing, dissolution, co-decontamination, separation and purification during wet reprocessing. After the spent fuel assembly is sheared and dissolved, the solution enters the subsequent chemical process for treatment, and the cladding of fuel element rod is retained in the dissolver, which is called leached hulls. It is one of the main sources of high-level radioactive waste in wet reprocessing process. Due to the accounting and control requirements of nuclear material production process during facility operation, as well as the needs of waste treatment and disposal, it is necessary to analyze the contents of uranium and plutonium in the cladding. In this paper, a method for indirect analysis of uranium and plutonium contents in leached hulls by γ spectroscopy was established. The leached hulls were measured by segment scanning, and the mass of ¹³⁷Cs in each layer of the leached hulls was analyzed. The ratio of ¹³⁷Cs and nuclear material can be used to calculate the uranium and plutonium mass. The physical law of nuclear material fission was utilized in this method, and the relationship between fission products and the mass of uranium and plutonium was established, and the mass of uranium and plutonium was indirectly obtained after obtaining the basic data through measurement and analysis. This method can be applied in leached hulls and spent fuel assembly burnup measurement and analysis, and provide technical support for facility operation, nuclear material accounting and waste management, etc. In the analysis of ¹³⁷Cs, the method of passive efficiency calibration was used to reconstruct the model of leached hulls and calculate the detection efficiency. In order to solve the limit of the number of sampled particles in the simulation calculation, the discrete division technique was used. In the experiment, ¹³⁷Cs point source was used to verify the method. The results show that the activity deviation between the measured value and standard value is less than 3%, which confirms the feasibility of the method.