Alignment detection method and display device

An alignment detection method for the alignment between a first substrate and a second substrate superimposed one on another, comprising:

• establishing a coordinate system;
• providing at least one group of a first mark region and a second mark region arranged on the first substrate and the second substrate respectively and opposite to each other, a plurality of first alignment marks being arranged at the first mark region and spaced apart from each other, a plurality of second alignment marks being arranged at the second mark region and spaced apart from each other, a distance between two adjacent first alignment marks being different from a distance between two adjacent second alignment marks, the first mark region and the second mark region being arranged opposite to each other to form at least two groups of first alignment marks and second alignment marks arranged opposite to each other;
• detecting an overlap level between an orthogonal projection of each of the first alignment marks onto the first substrate and an orthogonal projection of a corresponding one of the second alignment marks onto the second substrate, selecting a group of the first alignment mark and the second alignment mark having the highest overlap level, and acquiring, in the coordinate system, coordinate values of each of the first alignment mark and the second alignment mark in the group having the highest overlap level;
• and
• comparing the coordinate values of each of the first alignment mark and the second alignment mark with a threshold, to determine alignment accuracy between the first substrate and the second substrate.