Abstract: DZ-12/4 multi-energy electron linear accelerator was established at China Institute of Atomic Energy (CIAE). This device is mainly used as an electron beam irradiation experimental platform for radiation processing level. In this work, in order to detect the control parameter during the irradiation process of the DZ-12/4 multi-energy electron linear accelerator, the beam energy, one of the key parameters of the electron linear accelerator was measured using the FJL-02 radiochromic film dosimeter made by CIAE, and the reliability of the developed Faraday cup which is used as a beam monitoring system was verified. The results show that the energy of the DZ-12/4 multi-energy electron linear accelerator is adjustable in the range of 4-12 MeV, and the operating parameter is accurate and reliable. In daily operation, the accelerator operator can effectively control and estimate the irradiation dose by monitoring equipment and adjusting accelerator parameter, which has very good practicality and simplicity.