The　contents　of　solvent,　rosin　and　activator　were　adjusted　to　obtain　the　most　appropriate　proportion　of　the　flux　for　Sn-Bi　based　lead　free　solder　material　by　a　series　of　orthogonal　experiments.　Compared　with　some　commercial　Sn-Bi　based　solder　pastes,　some　tests　about　the　solder　paste,　such　as　solder　ball　test,　wettability　test　and　slump　test　had　been　carried　on.　It　was　found　that　the　self-made　Sn-Bi　based　solder　paste　had　an　excellent　performance.　The　welding　spots　had　good　appearance;　the　residues　solidified　well.　The　effect　of　the　solder　powder　ratio　on　rheological　and　printing　behavior　had　been　studied.　When　the　mass　ratio　was　12:88wt%,　the　best　rheological　and　printing　properties　of　solder　paste　could　be　obtained.