The invention discloses a high precision piston pin for an unmanned aerial vehicle and a preparation method of the high precision piston pin. A piston pin body of the high precision piston pin for the unmanned aerial vehicle is formed by low carbon alloy steel in a cold extrusion manner; a pin hole is formed through center extrusion; a first conical hole and a second conical hole are manufactured in the two ends of the pin hole correspondingly; the piston pin body is provided with a surface carburizing layer acquired as a whole through a heat treatment process, and a core portion hardness layer located below the surface carburizing layer; the outer surface of the piston pin body is machined by a high precision coreless grinding machine so that an outer circle surface can be acquired; after the piston pin body is formed by means of cold extrusion of a blank material, an outer circle is roughly ground, and then heat treatment is performed, wherein the carbon potential in a furnace is controlled at 0.8%-1.2% through carburizing quenching, temperature is risen to 890-910 DEG C and then is lowered to 860-880 DEG C, quenching treatment is performed, and ice cooling is performed after quenching; and the temperature in the furnace is controlled at 170-190 DEG C through tempering, the tempering time is 175-185 min, and the outer circle is accurately ground after discharging and natural cooling. The high precision piston pin for the unmanned aerial vehicle and the preparation method of the high precision piston pin have the beneficial effects of being stable in quality, long in service life and high in production efficiency.