[Objective] The aim of this study was to isolate microorganisms capable of degrading polyethylene materials, for example, agricultural mulch film. [Methods] By culturing the fungal strains with liner low-density polyethylene powder, we obtained a fugal strain with the ability of polyethylene degradation. Then we identified this strain by cultivation characters and molecular biology methods. Furthermore, we tested the degradation efficiency of agricultural mulch film of the fungus, weight loss of mulch, Fourier Transform infrared spectroscopy (FTIR) spectrogram and high-resolution field emission scanning electron microscope. [Results] Fungus PT1 capable of degrading agricultural mulch film was identified as Penicillium citrinum. PT1 could grow on linear low-density polyethylene powder with an average molecular weight of 2000 or 400000 as the sole carbon source. It could degrade low-density polyethylene powder and corrode traditional polyethylene film monitored by FTIR spectrogram and high-resolution field emission scanning electron microscope. The weight loss of polyester biodegradable film is about 50% after 35 days when co-cultured with PT1 strain. [Conclusion] A new fungus strain to degrade agricultural mulch film, P. citrinum PT1, was isolated and identified. Our finding provides a new friendly way to deal with agricultural mulch film.