A method for dynamic adjustment of video resolution when watching TV, sets a first, second, and third threshold values for a Received Signal Strength Indication (RSSI), the first threshold value being greater than the second threshold value and the second threshold value being greater than the third threshold value. A working mode of a receiving WI-FI device is detected. An RSSI value of WI-FI signals being received by a user terminal is calculated and the RSSI value is compared with first, second, and third threshold values. Taking working mode of the WI-FI device into account, the video resolution of video streams to be transmitted are adjusted according to results of comparisons and the adjusted video streams are transmitted to the user terminal.