Embodiments of the present disclosure provide a congestion control method, an apparatus, and a system. The method includes receiving, by a first device, an acknowledgement packet that is from a second device and that includes an ECE identifier. Based on an indication of the ECE identifier the first device starts monitoring a plurality of sub streams on a plurality of transmission paths between the first device and the second device, and grouping, into one set, sub streams that meet a congestion control condition. Additionally, intra-set congestion control is performed on the sub streams in the set. Separately congestion control is performed on a sub stream that is not in the set. The congestion control method is applied to a scenario in which data transmission is performed between the first device and the second device by using the MPTCP.