Manufacturing method of array substrate, array substrate and display device

The invention relates to the field of liquid crystal display, in particular to a manufacturing method of an array substrate, the array substrate and a display device. According to the array substrate, the thickness of a grid insulation layer between a source of the array substrate and a grid pattern and the thickness of a grid insulation layer between a drain of the array substrate and the grid pattern are larger than that of a grid insulation layer between a source layer and the grid pattern. Due to the fact that the grid insulation layer between the source and the grid pattern and the thickness of the grid insulation layer between the drain and the grid pattern are larger, capacitance between the source and a grid and capacitance between the drain and the grid are reduced, the corresponding capacitance of the source, the drain and the grid is lowered, pixel load is reduced, the power consumption of the whole display device is lowered, unnecessary power consumption is reduced, and meanwhile the display effect of the array substrate cannot be affected.