In　the　present　work,　the　effect　of　Ni　doping　on　the　microstructures　and　properties　of　Zn-20Sn　high　temperature　lead-free　solder　has　been　investigated.　Interestingly,　Ni　was　present　as　the　form　of　Ni-Zn　compounds　in　the　microstructure　of　Zn-20Sn-xNi　alloy.　When　the　Ni-doping　amount　was　0.2~0.4wt.%,　the　presence　of　δ　phase　was　found,　and　when　the　doping　amoun　was　0.8wt.%,　the　presence　of　γ　phase　was　observed.　With　the　increase　of　Ni　content,　the　liquidus　temperature　increased　but　the　solidus　temperature　did　not　change　obviously.　In　addition,　the　microhardness　and　electrical　resistivities　of　Zn-20Sn-xNi　solder　increased　gradually.　And　the　spreading　area　and　shear　strength　increased　firstly　but　decreased　afterwards.　When　the　content　of　Ni　was　0.4wt.%,　the　spreading　area　and　shear　strength　of　solder　reached　to　be　maximum.　After　the　addition　of　0.4　wt.%　Ni,　the　microstructure　of　the　interfacial　intermetallic　compound　(IMC)　layer　of　the　interface　didn＇t　change,　but　the　total　thickness　of　the　IMC　layer　reduced.　The　δ-phase　was　embedded　in　the　grain　boundary　of　ε-CuZn5,　which　hindered　the　diffusion　of　atoms.　The　thickness　of　IMC　layer　at　the　interface　reduced,　which　led　to　the　improvement　of　the　shear　strength　of　the　interface.　©　2019　Fujian　Institute　of　Research　of　the　Structure　of　Matter.　All　rights　reserved.