Some copper artifacts unearthed from the Xiao Mausoleum were joined by soldering. In this research, we analyzed the coppertin alloy and tin soldered red copper samples using optical and Scanning Electron Microscopy/Energy Dispersive XRay Spectroscopy. We found that the solder used in the artifacts from the Xiao Mausoleum is a coppertin alloy and not tinonly solder. There is only a small amount of literature available, and little experimental research on the welding technology using copper alloy. The simulated experiment in this paper may provide some information and guidance for future research.