The present disclosure provides a low-temperature polycrystalline silicon array substrate which includes a substrate, a groove disposed on the substrate, a buffer layer disposed on the substrate, and a polycrystalline silicon active layer disposed on the buffer layer, the groove is located at a channel of a thin film transistor, and the buffer layer covers the groove to form an air layer in the groove. The present disclosure further provides a manufacturing method of a low-temperature polycrystalline silicon array substrate, mainly including: manufacturing a groove at a channel of a thin film transistor on a substrate; depositing a metal sacrificial layer on the substrate, and etching the metal sacrificial layer except the groove through an etching process; sequentially forming a buffer layer and an amorphous silicon layer on the substrate; and removing the metal sacrificial layer in the groove to form an air layer in the groove.