Abstract: The micron powder solder of Sn-Ag-Cu-RE was prepared for the first time.The powder particles are spherical in shape, scattered over steps and the spread ability and spreading ratio of the powder solder are improved obviously.The solidus of the micron powder solder is in the range of 190.643℃-193.645℃ and the liquidus in the range of 216.963℃-218.368℃ which reduced 28℃ and 3℃ respectively compared with block solder.The experimental results indicate that the "surface effect" of the micron powder solder is remarkable, and it is a new method for the development and application of lead free solders.