Abstract: TiB₂/Cu composites with multi-particle (2 μm+10 μm+50 μm) were prepared by powder metallurgy. The arc erosion resistance of multi-particle TiB₂/Cu composites was tested in a JF04C contact material testing system. The arc erosion resistance and morphology of TiB₂/Cu composites were studied when the mass ratios of TiB₂ particles (2 μm+10 μm+50 μm) were 1∶1∶1, 1∶1∶3, 1∶3∶1 and 3∶1∶1, respectively. The results show that when the (2 μm+10 μm+50 μm) TiB₂ particle mass ratio is 1∶1∶1, the TiB₂/Cu composite has the highest relative density and conductivity of 99.1% and 87.1%IACS, respectively. When the (2 m+10 m+50 m) TiB₂ particle mass ratio are 1∶1∶1 and 1∶3∶1, the structure uniformity of the TiB₂/Cu composites is better, the material loss is the same after arc erosion, and the material loss of the TiB₂/Cu composite is lower than the composites with other ratios. When the ratio is 1∶3∶1, the TiB₂/Cu composite has the lowest average arc energy, and the arc duration and arc energy are the most stable. It can be concluded that the introduction of appropriate multi-particle TiB₂ particles into Cu matrix can improve the density and electrical conductivity of the TiB₂/Cu composites. In the process of arc erosion, TiB₂ particles with different sizes cooperate with each other, which is helpful to enhance the arc erosion resistance and service stability of the TiB₂/Cu composites.