A microarray including a plurality of detection areas and at least one mark is provided. The plurality of the detection areas are arranged in an array. The at least one mark is disposed among or beside the plurality of the detection areas. The at least one mark is configured for at least one of image focusing, positioning and splicing, wherein the at least one mark comprises a plurality of grid dots distributed in an area. The area comprises a plurality of zones arranged in an array, each of the plurality of the grid dots is disposed in one of the plurality of the zones, a number of the plurality of the grid dots is less than a number of the plurality of the zones, and the plurality of the grid dots form a two-dimensional pattern.