1. A method for acquiring an iris image, comprising: acquiring an image including an eye of a person; identifying a position of an eyeball in the image, comprising: identifying, by an iris image recognition device, a position of the eye in the image; and identifying, by the iris image recognition device, a position of a center of the eyeball based on the position of the eye; determining a parameter for photographing an iris based on the position of the eyeball, comprising: acquiring a predetermined eyeball radius; and determining a focal point and a focal length for capturing a near-infrared iris image based on the position of the center of the eyeball and the predetermined eyeball radius; and capturing the iris image based on the parameter.