Abstract: The purity of the brazing alloys is necessary to be improved with the increasing cleanness of steel.This paper aims at investigating the influence of trace calcium that is contained in filler metal during production process.The melting property, microstructure and spreading performance of BAg45Cu30Zn alloy with various calcium additions have been studied, by employing simultaneous thermal analyzer and scanning electron microscope.The results show that the solidus temperature increases, the liquidus temperature decreases and the melting range narrows, with the calcium content increasing in alloy.The element calcium in the form of CaO exists as the crystal nucleus to refine alloy microstructure.The spreading performance of alloy on 316LN stainless steel has been weakened, resulting from the existence of calcium element.