Head-Up Display and Head-Up Display Method

A head-up display includes a picture generation unit and a first lens. The picture generation unit is configured to output a first light ray and a second light ray. The first light ray is used to output and display a first picture, and the second light ray is used to output and display a second picture. When the first lens is at the first position, the first light ray and the second light ray do not pass through the first lens. When the first lens is at the second position, the first light ray passes through the first lens. The head-up display can implement switching between a single image plane and a plurality of image planes.