The present disclosure relates to an array substrate, a manufacturing method thereof, and a display panel, the array substrate including: a substrate, and a low temperature polysilicon layer, an inorganic film group layer, and a source/drain layer disposed on the substrate in sequence. The substrate includes a display region, the low temperature polysilicon layer located at the display region, the inorganic film group layer provided with a through hole, and an angle between a sidewall and a bottom wall of the through hole is not less than 100 degrees; the source/drain layer covering the sidewall and the bottom wall of the through hole to be connected to the low temperature polysilicon layer.