The invention relates to a thin film transistor liquid crystal display (TFT-LCD) array substrate and a manufacturing method thereof, wherein the manufacturing method comprises the following steps of: 1, depositing a gate metal thin film on a substrate, forming a figure consisting of a gate electrode and a gate line through a first-time composition process; 2, depositing a gate insulating thin film, a semiconductor thin film and a barrier thin film on the substrate subjected to the step 1, forming figures of a semiconductor layer and a barrier layer through a second-time composition process, wherein the barrier layer is used for preventing the semiconductor layer from being etched; and 3, depositing an ohmic contact thin film, a transparent conductive thin film, a source-drain metal thin film and a passivated thin film on the substrate subjected to the step 2, and forming the figures of a source electrode, a drain electrode, a thin film transistor (TFT) channel, a data line, a pixel electrode and a passivation layer through a third-time composition process. The invention can reduce the thickness of the semiconductor layer and the off-state current of a TFT and enhance the performance of the TFT by adopting three times of the composition processes and arranging the barrier layer between the semiconductor layer and an ohmic contact layer in a clamping way.