A flip-chip underfill method is proposed for the purpose of underfilling a gap formed beneath a semiconductor chip mounted in a flip-chip manner over an underlying surface. The flip-chip underfill method comprises the following procedural steps of: preparing a dispensing needle having an outlet; then, moving the dispensing needle in such a manner as to position the outlet thereof at a corner point between the upper surface and the sidewall of the semiconductor chip; and finally injecting resin at the targeted corner point, which allows the injected resin from the outlet of the dispensing needle to flow down along the sidewall of the semiconductor chip to the edge of the lower surface of the semiconductor chip and subsequently fill into the gap through capillary action. This flip-chip underfill method is more advantageous to use than the prior art since it allows the dispensing needle to be unobstructed by any gold wires or passive components mounted beside the chip and also allows the injected resin to be substantially confined to the targeted area beneath the chip without being wasted.