A method for sending a high-definition digital video signal, comprising: encoding the high-definition digital video signal in a line-by-line sequence to obtain digital modulation line signals; wherein each of the digital modulation line signals comprises an effective modulation signal comprising a chrominance modulation signal and a brightness modulation signal, wherein the chrominance modulation signal is determined according to component chrominance signals and a chrominance subcarrier, and a chrominance subcarrier frequency is determined in a predetermined frequency range higher than a frequency range of a video baseband of a brightness of the high-definition video signal and in a predetermined bandwidth range; converting the digital modulation line signals into analog video line signals; and sending the analog video line signals; wherein before the encoding the high-definition digital video signal in a line-by-line sequence to obtain digital modulation line signals, the method further comprises: reserving, for a current high-definition digital video data frame to be processed, data points in an active data area and a part of data points in a column direction in a blank area in the data frame to obtain an intermediate data frame; and the encoding the high-definition digital video signal in the line-by-line sequence to obtain the digital modulation line signals further comprises: encoding each line of data in the active data area in the intermediate data frame to obtain a digital modulation line signal. encoding the high-definition digital video signal in a line-by-line sequence to obtain digital modulation line signals; wherein each of the digital modulation line signals comprises an effective modulation signal comprising a chrominance modulation signal and a brightness modulation signal, wherein the chrominance modulation signal is determined according to component chrominance signals and a chrominance subcarrier, and a chrominance subcarrier frequency is determined in a predetermined frequency range higher than a frequency range of a video baseband of a brightness of the high-definition video signal and in a predetermined bandwidth range; converting the digital modulation line signals into analog video line signals; and sending the analog video line signals; wherein before the encoding the high-definition digital video signal in a line-by-line sequence to obtain digital modulation line signals, the method further comprises: reserving, for a current high-definition digital video data frame to be processed, data points in an active data area and a part of data points in a column direction in a blank area in the data frame to obtain an intermediate data frame; and the encoding the high-definition digital video signal in the line-by-line sequence to obtain the digital modulation line signals further comprises: encoding each line of data in the active data area in the intermediate data frame to obtain a digital modulation line signal. reserving, for a current high-definition digital video data frame to be processed, data points in an active data area and a part of data points in a column direction in a blank area in the data frame to obtain an intermediate data frame; and the encoding the high-definition digital video signal in the line-by-line sequence to obtain the digital modulation line signals further comprises: encoding each line of data in the active data area in the intermediate data frame to obtain a digital modulation line signal.