Solder paste is a new type of soldering material that has emerged with surface mount technology (SMT). Solder paste is a complex system composed of a mixture of solder powder, flux, and other additives. Solder paste is divided into two types: halogen-free and halogenated. Among them, halogen-free solder paste has excellent printing performance, can maintain its viscosity and stability for a longer time after printing on PCB board, and is also more environmentally friendly. Therefore, it is necessary to monitor halogens during the preparation of solder paste and the use of raw materials.