A multi-chip package structure includes a first chip, a second chip, a circuit layer, a plurality of first conductive bumps, a plurality of second conductive bumps and an underfill. The first chip has a chip bonding region, a plurality of first inner pads and first outer pads. The circuit layer is disposed on the first chip and includes a plurality of insulating layers and at least one metal layer. The insulating layers have a groove disposed between the first inner pads and the first outer pads and surrounding the first inner pads. The first conductive bumps are disposed on the first outer pads. The second chip is flipped on the chip bonding region. Each first inner pad is electrically connected to a second pad of the second chip through the second conductive bump. The underfill is disposed between the first and second chips and covers the second conductive bumps.