An array substrate, a manufacturing method thereof, a display panel and a display device are disclosed. The manufacturing method includes: forming a first metal wiring, an interlayer insulating film, a second metal wiring and a protecting layer in sequence on a substrate, the second metal wiring is parallel with the first metal wiring and has an overlapped area therewith which is defined as a first zone, and portions of the first and second metal wiring except the first zone are defined as a second zone and a third zone respectively; at least thinning a portion of the interlayer insulating film and/or the protecting layer corresponding to the first zone while leaving portions except those corresponding to the first, second and third zones un-thinned. The manufacturing method can mitigate Zara mura.