A method of manufacturing an LED package structure for preventing lateral light leakage, comprising: placing a plurality of light-emitting units on a carrier substrate, wherein the light-emitting units are electrically connected to the carrier substrate; forming a plurality of light-transmitting gel bodies on the carrier substrate for respectively enclosing the light-emitting units, wherein the light-transmitting gel bodies are separated from each other to form a gel receiving space among the light-transmitting gel bodies; forming a light-shielding gel body to fill up the gel receiving space; and cutting the carrier substrate and the light-shielding gel body to form the plurality of LED package structures separated from each other, wherein the carrier substrate is cut to form a plurality of circuit substrates for respectively carrying the light-emitting units; wherein each light-emitting unit includes at least one LED chip, each light-transmitting gel body has a first light-transmitting portion disposed on the corresponding circuit substrate for enclosing the at least one LED chip of the corresponding light-emitting unit and at least one second light-transmitting portion projected upwardly from the first light-transmitting portion and corresponding to the at least one LED chip of the corresponding light-emitting unit, and the at least one second light-transmitting portion has a light output surface on the top side of the light-transmitting gel body and an outer perimeter surface connected between the light output surface and the first light-transmitting portion, wherein the first light-transmitting portion and the outer perimeter surface of the at least one second light-transmitting portion of each light-transmitting gel body are enclosed by the light-shielding gel body, characterized by the top surface of the light output surface of the at least one second light-transmitting portion is higher than the top surface of the light-shielding gel body; wherein the maximum diameter of the at least one second light-transmitting portion is smaller than the diameter of the first light-transmitting portion, and the minimum diameters (d5, d6) of the light output surface of the at least one second light-transmitting portion varies inversely as the heights (H1, H2) from the top surface of the light-shielding gel body to the first light-transmitting portion, respectively. placing a plurality of light-emitting units on a carrier substrate, wherein the light-emitting units are electrically connected to the carrier substrate; forming a plurality of light-transmitting gel bodies on the carrier substrate for respectively enclosing the light-emitting units, wherein the light-transmitting gel bodies are separated from each other to form a gel receiving space among the light-transmitting gel bodies; forming a light-shielding gel body to fill up the gel receiving space; and cutting the carrier substrate and the light-shielding gel body to form the plurality of LED package structures separated from each other, wherein the carrier substrate is cut to form a plurality of circuit substrates for respectively carrying the light-emitting units; wherein each light-emitting unit includes at least one LED chip, each light-transmitting gel body has a first light-transmitting portion disposed on the corresponding circuit substrate for enclosing the at least one LED chip of the corresponding light-emitting unit and at least one second light-transmitting portion projected upwardly from the first light-transmitting portion and corresponding to the at least one LED chip of the corresponding light-emitting unit, and the at least one second light-transmitting portion has a light output surface on the top side of the light-transmitting gel body and an outer perimeter surface connected between the light output surface and the first light-transmitting portion, wherein the first light-transmitting portion and the outer perimeter surface of the at least one second light-transmitting portion of each light-transmitting gel body are enclosed by the light-shielding gel body, characterized by the top surface of the light output surface of the at least one second light-transmitting portion is higher than the top surface of the light-shielding gel body; wherein the maximum diameter of the at least one second light-transmitting portion is smaller than the diameter of the first light-transmitting portion, and the minimum diameters (d5, d6) of the light output surface of the at least one second light-transmitting portion varies inversely as the heights (H1, H2) from the top surface of the light-shielding gel body to the first light-transmitting portion, respectively.