A manufacturing method of an array substrate, comprising the following steps: S1 forming a gate signal line and a gate electrode on a base substrate, successively depositing a gate insulating layer, an active layer, and a metal layer, faulting a mask formed of photoresist on the metal layer, and removing the metal layer outside a region for forming a data line and source/drain electrodes through the mask; S2. simultaneously etching the active layer and ashing the photoresist so as to expose the metal layer within a channel region; S3. etching the active layer exposed by the photoresist after being ashed after the step S2; S4. removing the metal layer within the channel region.