A fan-out packaging method includes: prepare circuit patterns on one side or both sides of a substrate; install electronic parts on one side or both sides of the substrate; prepare packaging layers on both sides of the substrate; the packaging layers on both sides of the substrate package the substrate, the circuit patterns, and the electronic parts, the packaging layers being made of a thermal-plastic material; wherein the substrate is provided with a via hole; both sides of the substrate are communicated by means of the via hole; a part of the packaging layers penetrate through the via hole when the packaging layers are prepared on both sides of the substrate; and the packaging layers on both sides of the substrate are connected by means of the via hole.