A service protection method for a composite link, characterized in that it comprises: a node of a member link in a composite link sending a notification message to a control unit of the composite link when detecting that services of the member link are congested or bandwidth thereof changes; and the control unit of the composite link adjusting service traffic distributed to the member link according to information carried in the notification message; wherein, if the node detects that the services of the member link are congested, the information carried in the notification message at least comprises: link change type and congestion packet loss rate; the step of the control unit of the composite link adjusting the service traffic distributed to the member link according to the information carried in the notification message comprises: the control unit of the composite link decreasing the service traffic of the member link according to the congestion packet loss rate, and redistributing the decreased service traffic to other member links; if the node detects that the bandwidth of the member link changes, then the information carried in the notification message at least comprises: link change type and current actual bandwidth of the member link; the step of the control unit of the composite link adjusting the service traffic distributed to the member link according to the information carried in the notification message comprises: the control unit of the composite link comparing the current actual bandwidth of the member link with actual bandwidth of the member link carried in a last notification message; if the current actual bandwidth of the member link is smaller than the actual bandwidth of the member link in the last notification message, and is smaller than an amount of services which are currently carried, decreasing the service traffic of the member link according to a bandwidth decrease amount, and distributing the decreased service traffic to other member links; if the current actual bandwidth of the member link is larger than the actual bandwidth of the member link in the last notification message, and a protection mode of the member link is configured as a return mode, increasing the service traffic of the member link according to a bandwidth increase amount, if the protection mode of the member link is configured as a non-return mode, not adjusting the service traffic distributed to the member link. a node of a member link in a composite link sending a notification message to a control unit of the composite link when detecting that services of the member link are congested or bandwidth thereof changes; and the control unit of the composite link adjusting service traffic distributed to the member link according to information carried in the notification message; the control unit of the composite link decreasing the service traffic of the member link according to the congestion packet loss rate, and redistributing the decreased service traffic to other member links; if the node detects that the bandwidth of the member link changes, then the information carried in the notification message at least comprises: link change type and current actual bandwidth of the member link; the step of the control unit of the composite link adjusting the service traffic distributed to the member link according to the information carried in the notification message comprises: the control unit of the composite link comparing the current actual bandwidth of the member link with actual bandwidth of the member link carried in a last notification message; if the current actual bandwidth of the member link is smaller than the actual bandwidth of the member link in the last notification message, and is smaller than an amount of services which are currently carried, decreasing the service traffic of the member link according to a bandwidth decrease amount, and distributing the decreased service traffic to other member links; if the current actual bandwidth of the member link is larger than the actual bandwidth of the member link in the last notification message, and a protection mode of the member link is configured as a return mode, increasing the service traffic of the member link according to a bandwidth increase amount, if the protection mode of the member link is configured as a non-return mode, not adjusting the service traffic distributed to the member link. the control unit of the composite link comparing the current actual bandwidth of the member link with actual bandwidth of the member link carried in a last notification message; if the current actual bandwidth of the member link is smaller than the actual bandwidth of the member link in the last notification message, and is smaller than an amount of services which are currently carried, decreasing the service traffic of the member link according to a bandwidth decrease amount, and distributing the decreased service traffic to other member links; if the current actual bandwidth of the member link is larger than the actual bandwidth of the member link in the last notification message, and a protection mode of the member link is configured as a return mode, increasing the service traffic of the member link according to a bandwidth increase amount, if the protection mode of the member link is configured as a non-return mode, not adjusting the service traffic distributed to the member link.