Based on mechanisms of single energy photon interaction in an HPGe detector

the Monte Carlo Code method was used for simulating the energy response curves of single-energy photon in HPGe detector and characteristic parameters of the curves were abstracted. The theoretic response spectrum expression under different single energy incident photons was obtained by least-squares fit to the parameters. The theoretic expression was calibrated by experimental data with various kinds of gamma-ray sources. The corrected expression can provide reference for continuous photon spectrum unscrambling.