The present invention is applicable to the field of electronic component technologies and provides a manufacturing method of a self-aligned metal oxide TFT component, including: selecting a substrate and preparing a gate on the substrate; successively disposing an insulation layer, a transparent electrode layer, and a photoresist on the gate; using the gate as a mask to perform exposure from a back side of the substrate, so as to form a source and a drain that are aligned with the gate; depositing a metal oxide semiconductor layer on the transparent electrode layer; performing etching on the semiconductor layer, the source, and the drain, so that outer ends of the source and the drain are exposed out of the metal oxide semiconductor layer; and depositing a passivation layer and leading out the source and the drain. In the present invention, a transparent conductor is used as the electrode layer, and a bottom gate is used as a mask to perform back exposure, so as to perform etching on the source and the drain, thereby implementing a self-alignment between the source or the drain and the gate, effectively reducing parasitic capacitance, and improving component performance. The component is of a bottom-gate bottom-contact structure, and there is no need to manufacture an etch-stop layer, thereby simplifying a process, reducing use of a photolithographic mask, improving production efficiency, and improving an electrical property of the component.