The present disclosure discloses a method and system for switched display of a grayscale of a multi-line scan light-emitting diode (LED), and relates to the field of LED display technology. In view of the problems in the prior art that a multi-line scan constant-current source chip has an insufficient refresh rate, a low grayscale level, and a poor low-grayscale effect, the present disclosure provides a method during the display of relatively high grayscales, a display cycle is scrambled. During the display of relatively low grayscales, the grayscales are combined. In the present disclosure, a relatively high refresh rate and a grayscale level can still be ensured in a case of a relatively large quantity of line scans. In addition, in the case of low-grayscale display, the problems such as low-grayscale speckles, slightly dark low-grayscale, and relatively poor low-grayscale linearity are resolved, thereby improving a picture display effect.