A fabricating method for the self-drilling screw has acts of forming a main section and a secondary section by punching, forming a flat drilling blade with a tapered end at a bottom end of the small diameter portion by punching, and forming a thread portion on an outer surface of the main section and a chip removal thread portion with a spiral chip removal groove on an outer surface of the secondary section by rolling. The self-drilling screw utilizes the flat drilling blade with the tapered end and the chip removal section having chip removal function to reduce the size of the drilling blade. Therefore, the self-drilling screw reduces the size of the punching die, lowers the punching force, lowers both the load of the punching die and the load of the punching machine, and lowers both the die cost and the manufacturing cost.