A method for positioning a solder ball onto a contact tail of an electrical connector comprises several steps. Firstly, arrange the contact tail into a center region and a peripheral region surrounding the center region. Secondly, attach solder paste onto the center region of the contact tail via a first mesh painting procedure. Thirdly, attach solder resist onto the peripheral region of the contact tail via a second mesh painting procedure. Fourthly, position a solder ball on the center region of the contact tail via a screen board. Fifthly, apply a reflow soldering procedure on the solder ball so that the solder ball can be soldered on the solder paste attached to the center region of the contact tail.