The present disclosure provides a method for manufacturing an array substrate, an array substrate and a display device. The method includes: forming a gate line, a gate electrode and an insulating layer which covers the gate line and the gate electrode on a first surface of a substrate; forming a semiconductive film on the insulating layer; patterning the semiconductive film using the gate electrode and the gate line as a mask, so as to form an source semiconductive layer at a region where the gate line and the gate electrode are located; and manufacturing a target semiconductive layer using the source semiconductive layer.