Manufacturing method of film transistor structure

The invention discloses a manufacturing method of a film transistor structure. A photoresistive pattern layer is formed on an active pattern layer and a part of grid electrode insulating layer so as to expose a source electrode predetermined position and a drain electrode predetermined position of the grid electrode insulating layer. The photoresistive pattern layer comprises a plurality of inverted-trapezoid blocks and can also be used as a mask so as to deposit a metal layer on the photoresistive pattern layer, the source electrode predetermined position and the drain electrode predetermined position. After the photoresistive pattern layer and the metal layer thereon are removed, the residual metal layer patterns are converted into a source electrode and a drain electrode. According to the invention, the manufacturing process is simplified, and an etching barrier layer for protecting back channels is not formed.