A method for reducing digital subscriber line interference, comprising: identifying at least one legacy digital subscriber line which does not support a vectored capability set in a digital subscriber line set, wherein the digital subscriber line set comprises at least one vectored digital subscriber line and the legacy digital subscriber line; obtaining a target power spectral density mask value of the legacy digital subscriber line, wherein the target power spectral density mask value is a reference value for reducing interference of the legacy digital subscriber line on the vectored digital subscriber line; wherein the target power spectral density mask value comprises an upstream target power spectral density mask value; and reducing power spectral density of a transmit signal on the legacy digital subscriber line according to the target power spectral density mask value; wherein the reducing power spectral density of a transmit signal on the legacy digital subscriber line according to the target power spectral density mask value comprises: using a smaller value between an upstream power spectral density mask value that is obtained last time or during initialization and the upstream target power spectral density mask value to obtain a current upstream power spectral density mask value; and sending the current upstream power spectral density mask value to a terminal in a digital subscriber line system, so that the terminal reduces power spectral density of an upstream signal on the legacy digital subscriber line, when confining channel discovery power spectral density to be not more than the smallest value in values obtained by subtracting 3.5 dB separately from an upstream maximum mask value during a start phase of a channel discovery phase, an upstream power back-off mask value, and the current upstream power spectral density mask value. identifying at least one legacy digital subscriber line which does not support a vectored capability set in a digital subscriber line set, wherein the digital subscriber line set comprises at least one vectored digital subscriber line and the legacy digital subscriber line; obtaining a target power spectral density mask value of the legacy digital subscriber line, wherein the target power spectral density mask value is a reference value for reducing interference of the legacy digital subscriber line on the vectored digital subscriber line; wherein the target power spectral density mask value comprises an upstream target power spectral density mask value; and reducing power spectral density of a transmit signal on the legacy digital subscriber line according to the target power spectral density mask value; wherein the reducing power spectral density of a transmit signal on the legacy digital subscriber line according to the target power spectral density mask value comprises: using a smaller value between an upstream power spectral density mask value that is obtained last time or during initialization and the upstream target power spectral density mask value to obtain a current upstream power spectral density mask value; and sending the current upstream power spectral density mask value to a terminal in a digital subscriber line system, so that the terminal reduces power spectral density of an upstream signal on the legacy digital subscriber line, when confining channel discovery power spectral density to be not more than the smallest value in values obtained by subtracting 3.5 dB separately from an upstream maximum mask value during a start phase of a channel discovery phase, an upstream power back-off mask value, and the current upstream power spectral density mask value. using a smaller value between an upstream power spectral density mask value that is obtained last time or during initialization and the upstream target power spectral density mask value to obtain a current upstream power spectral density mask value; and sending the current upstream power spectral density mask value to a terminal in a digital subscriber line system, so that the terminal reduces power spectral density of an upstream signal on the legacy digital subscriber line, when confining channel discovery power spectral density to be not more than the smallest value in values obtained by subtracting 3.5 dB separately from an upstream maximum mask value during a start phase of a channel discovery phase, an upstream power back-off mask value, and the current upstream power spectral density mask value.