An array substrate, a method of manufacturing thereof, and a display panel are provided. In the array substrate, a lesser thickness of an active layer in a GOA area achieves improved response time of thin film transistor in the GOA area, and a greater thickness of the active layer in a display area reduces diffusion of photons in the active layer, so as to decrease an influence of negative bias of thin film transistor in the display area. Additionally, different demands for characteristics of the array substrate in the display area and in the GOA area may be met, such that quality of the display panel may be improved.