The invention relates to a method for dynamically adjusting a switch frequency of a burst mode for a liquid crystal display. The method of the invention comprises the steps of: (a) receiving a scan frequency value from a signal source; (b) deriving a switch frequency value of the burst mode according to the scan frequency value; and (c) transmitting the switch frequency value to a lamp controller. According to the method of the invention, the switch frequency value can be obtained through calculation or by a look-up table. The stitch frequency value preferably equals a scan frequency value multiplied by a multiple (N+0.5), wherein N is a positive number. A tolerable range of the switch frequency value of the burst mode is .+-.20 Hz. The method of the invention utilizes various scan frequency values to adjust the switch frequency value. Therefore, no matter what a scan frequency value is provided by the signal source, the switch frequency value can be dynamically adjusted according to the scan frequency value so as to eliminate or decrease a water flow on the display. Thus, the eyes of people will not sense the water flow on the display.