A synchronized video stream switching method for a video wall system. The video wall system includes a transmitter having first and second channels, and a receiver having third and fourth channels. The method includes: (a) After receiving a control command, the transmitter uses the first channel to transmit the first video stream to the third channel, and uses the second channel to transmit a pre-switch command to the fourth channel. (b) After receiving the pre-switch command, the receiver preserves the first video stream in the third channel. (c) After the switching event occurs at the transmitter in response to the control command, the transmitter transmit the second video stream via the first channel, but the receiver continues to preserve the first video stream in the third channel within a predetermined time period. (d) After the predetermined time period, the receiver accepts the second video stream in the third channel.