Background: The running of the nuclear system would produce a mass of radioactive waste

and the nuclide residual in these radioactive waste had to be analyzed. Purpose: The aim is to provide a main support to solve the problem of waste classifying and disposal by the quantitative analysis of the nuclide residual in the radioactive waste by gamma-ray spectra. Methods: The nuclide distribution has been researched by solving the weighted factor in every layer based on the hypothesis of layered uniform distribution

which could provide an important support for the calculation of detecting efficiency. Results: The weighted factor in every layer was calculated based on the hypothesis of layered uniform distribution. The measurement results from two different orientations

and the more accurate efficiency of source-peak were acquired. Conclusion: The results show that it is feasible to acquire the nuclide distribution by two-time measurement and solving the non-negative result of the matrix equation.Cited