Embodiments of the present invention provide a method, an apparatus, and a system for supporting a non-vector line. The method includes: selecting n non-vector lines TL from lines that are in an initializing stage, where n is an integer greater than or equal to 1; controlling to perform no further initializing for other lines that are in the initializing stage except the TL until the TL fully enters a data transmission stage; and before the TL enters the data transmission stage, estimating a far-end crosstalk coefficient CTL-SV from the TL to a vector line SV that is in the data transmission stage, where the CTL-SV is used in signal processing to eliminate far-end crosstalk caused by the TL to the SV.