Manufacturing method for thin film transistor

Disclosed is a manufacturing method for a thin film transistor. The manufacturing method steps include sequentially forming a grid electrode, a gate insulating layer and a semi-conductor layer on a substrate; forming a first photoresist pattern on the semi-conductor layer; taking the first photoresist pattern as a mask for patterning the semi-conductor to form a channel; taking a photomask as the mask for patterning the first photoresist pattern to form a channel protecting pattern; forming a conducting layer to cover the channel protecting pattern and the channel; forming a second photoresist material layer on the conducting layer; further taking the photomask as the mask for patterning the second photoresist material layer to form a second photoresist pattern; and taking the second photoresist pattern as the mask for patterning the conducting layer to form a source electrode and a drain electrode. One of the first photoresist pattern and the second photoresist pattern is a positive photoresist, and the othe