A chip package structure is provided. The chip package structure includes a substrate. The chip package structure also includes a first chip structure and a second chip structure over the substrate. The chip package structure further includes an anti-warpage bar over a first portion of the first chip structure and over a second portion of the second chip structure. A width of the anti-warpage bar overlapping the second portion of the second chip structure is greater than a width of the anti-warpage bar overlapping the first portion of the first chip structure.