Abstracts In the process of surface treatment by electron cyclotron resonance (ECR) plasma source, the magnetic field plays an important role in introducing the confinement of electrons. To investigate the influence of the magnetic field configuration on electron distribution conditions, this study presents a two-dimensional model of the ECR plasma source. According to the resulting distributions of the electron density and temperature, it is found that the plasma density in the mirror magnetic field is higher than that in the divergent magnetic field. At the same time, the application of the mirror magnetic field is valid for decreasing the electron temperature due to both effects of plasma confinement and particle collisions. Furthermore, the decrease of the minimum strength of the mirror magnetic field and the increase of the strength at the injection side contribute to higher electron density and lower electron temperature owing to the gradient of magnetic field.