Abstract: This paper presents a theoretical analysis model based on the parapotential flow and “fourphase” charge flow models.The model could more exactly describe the physics process in a low-impedance MA intense pinched beam diode. In the model, the evolution of electrons is divided into three phases:no pinching phase, weak pinch phase and tight pinch phase,and in each phase a proper empirical formula is provided for writing the characters of electron beam. Using the KARAT PIC program, the evolution process of electron flow was simulated in the diode, which was designed to test on the Qiangguang-I accelerator for producing intensive current pinched electron beam. Moreover, the experiment with the diode was carried out on QiangguangI accelerator. The contrast between simulated and experimenta