A display panel and a manufacturing method thereof are disclosed. Compared with the existing method of forming an under-cut structure through two processes of lithographing and wet etching, the manufacturing method of this disclosure can form the under-cut structure on a passivation layer through one etching process to save the production capacity, to form a double support to an organic light-emitting layer and a cathode through the cooperation of a planarization layer and an anode layer, to enhance a support strength of the cathode to the organic light-emitting layer, and to avoid the collapse risk.