1. A visual acuity test method, which comprises the steps of: displaying a test picture which includes at least one optotype on a display screen, and determines an active optotype for visual acuity test from the at least one optotype of the test picture; obtaining, from the visual acuity test subject, indication information for the active optotype of the test picture; and determining the visual acuity level of the visual acuity test subject according to orientations represented by the active optotype of the test picture and the indication information for the active optotype of the test picture; wherein at least two test pictures are displayed, each of which corresponds to a different visual acuity level, and wherein the at least two test pictures are displayed individually on the display screen; wherein, before the step of displaying the test picture on the display screen, the method further comprises: obtaining a first distance between the visual acuity test subject and the display screen; the step of displaying the test picture on the display screen comprises: according to a preset standard proportional relation and the first distance, proportionally determining a size corresponding to the first distance and adaptively adjusting the test picture with the size corresponding to the first distance; wherein the preset standard proportional relation includes: a standard distance between the visual acuity test subject and the display screen, and a standard test picture size corresponding to the standard distance.