A packaging substrate includes a first dielectric layer, a first circuit layer, a first metal bump, and a built-up structure. The first metal bump and the first circuit layer are embedded in and exposed from two surfaces of the first dielectric layer. The end of the first metal bump is embedded in the first circuit layer and between the first circuit layer and the first dielectric layer. In addition, a conductive seedlayer is disposed between the first circuit layer and the first metal bump. The built-up structure is disposed on the first circuit layer and the first dielectric layer. The outmost layer of the built-up structure has a plurality of conductive pads. Compared to the prior art, the present invention can effectively improve the warpage problem of the conventional packaging substrate.