A fabrication method of a hole structure, the method comprising: forming a first initial thin film made of organic insulating material on a base substrate; performing a first photolithography process on the first initial thin film with a pattern region of a mask to form a first thin film and a first hole, which is a through-hole located in the first thin film, wherein, the first hole has an opening on a surface of the first thin film away from the base substrate; forming a second initial thin film made of inorganic insulating material covering the first thin film; and performing a second photolithography process on the second initial thin film with the pattern region of the mask to form a second thin film and a second hole, which is a through-hole running through the second thin film and communicating with the first hole, wherein, the second hole has a first opening close to the base substrate and a second opening away from the base substrate, and a dimension of the second opening in a preset direction parallel to the base substrate is larger than a dimension of the first opening in the preset direction; before forming the first thin film, forming a third thin film, made of inorganic insulating material, on the base substrate, such that the third thin film, the first thin film and the second thin film are disposed in this order on the same side of the base substrate, the third thin film being closest to the base substrate, and forming a third hole, which is a through-hole located in the third thin film and communicates with the first hole on the base substrate such that the walls of the third hole are covered by the first thin film; wherein a dimension of an end portion of the first hole close to the base substrate in the preset direction is smaller than a dimension of an end portion of the third hole close to the base substrate in the preset direction; and a sloped angle of the first hole, which is the angle formed between the wall of the hole and the base substrate outside of the hole, is smaller than or equal to 45. forming a first initial thin film made of organic insulating material on a base substrate; performing a first photolithography process on the first initial thin film with a pattern region of a mask to form a first thin film and a first hole, which is a through-hole located in the first thin film, wherein, the first hole has an opening on a surface of the first thin film away from the base substrate; forming a second initial thin film made of inorganic insulating material covering the first thin film; and performing a second photolithography process on the second initial thin film with the pattern region of the mask to form a second thin film and a second hole, which is a through-hole running through the second thin film and communicating with the first hole, wherein, the second hole has a first opening close to the base substrate and a second opening away from the base substrate, and a dimension of the second opening in a preset direction parallel to the base substrate is larger than a dimension of the first opening in the preset direction; before forming the first thin film, forming a third thin film, made of inorganic insulating material, on the base substrate, such that the third thin film, the first thin film and the second thin film are disposed in this order on the same side of the base substrate, the third thin film being closest to the base substrate, and forming a third hole, which is a through-hole located in the third thin film and communicates with the first hole on the base substrate such that the walls of the third hole are covered by the first thin film; wherein a dimension of an end portion of the first hole close to the base substrate in the preset direction is smaller than a dimension of an end portion of the third hole close to the base substrate in the preset direction; and a sloped angle of the first hole, which is the angle formed between the wall of the hole and the base substrate outside of the hole, is smaller than or equal to 45.