An array substrate, a manufacturing method thereof and a display device are provided. The array substrate includes a first conductive pattern, an insulation layer covering the first conductive pattern, and a second conductive pattern arranged on the insulation layer. The insulation layer includes a via-hole through which the first conductive pattern is connected to the second conductive pattern. A conductive post connected to the first conductive pattern and the second conductive pattern is formed in the via-hole.