Abstract: To solve the problem of ultraviolet imaging device sealing leakage between the photocathode and the tube body, we deeply analyzed the quality problem of the tube body InSn alloy in melting process,and found out the solder melting layer defect came mainly from the incompletely solder degassing, the basal surface oxidation and the equipment contaminated with oil.Through optimizing the process parameters, we improved the process quality and changed the indium equipment of the tube body aside solder melting into casting molten,to make the qualified rate of the tube body solder melting reache 100% and the qualified rate of gas tightness between photocathode and tube body sealing yield to 98%.