Abstract: This paper studies the characteristics of vacuum surface arc discharge process and products for micro-cathode arc thruster (μ-CAT). The formation and evolution process of discharge plasma under the action of the electric pulse is studied and the spatial-temporal evolution of plasma channel and plume under different magnetic fields is analyzed by combining with discharge parameters, radiation spectrum and high-speed image diagnosis. The macro and micro characteristics of the discharge ablation products with stainless steel and titanium electrodes are obtained by collecting the splash products for morphology analysis. The results indicate that the discharge initiates from the electrode triple junction (TJ), and then partial discharge of the coating forms a surface discharge channel connecting the two electrodes. Applying a magnetic field of 100 mT magnitude can improve the discharge continuity and plume morphology (the luminous cross-section can reach two times that in the absence of magnetic field). After discharge, the electrode thermal product spray can last for 50~60 μs, and there are differences between the cathode and anode. From view of the collected splash products, the deposition of metal electrode materials is mainly composed of uniformly distributed nanoparticles, while the Si wafer above the electrode presents the morphology of micron-sized amorphous graphite. The typical characteristics of the splash products and electrode ablation pool are affected by the electrode material. The product particle size and electrode ablation pit size of stainless steel are more affected than those of titanium electrodes. Therefore, the magnetic field and electrode material have a significant impact on the vacuum surface discharge process and product morphology Consequently, these factors directly affect the performance of μ-CAT.