the present invention relates to a thin film transistor substrate and a fabricating method thereof . the thin film transistor according to one embodiment of the present invention comprises : a gate wire and a data wire formed to cross each other on an insulating substrate and define a pixel area ; a thin film transistor formed on the intersection of the gate wire and the data wire ; an inorganic insulating layer covering the thin film transistor and having a surface that a prominence and depression pattern formed on ; and a reflective layer provided on the prominence and depression pattern . thus , the present invention provides a thin film transistor substrate and a fabricating method thereof , which reduce the time required in the process and enhance the productivity .