A method for adjusting a line interface rate in an OTN system, the method comprising: determining, by a first node, an adjustment requirement for a line interface rate (step 410a); and adjusting, by the first node and according to the adjustment requirement for the line interface rate, a transport bandwidth of an optical channel OCh link, adjusting the number of optical channel transport lanes OTLs in an optical channel transport unit OTUCn link, and adjusting the number of optical channel data lanes ODLs in an optical channel data unit ODUCn link, wherein the OTL is in one-to-one correspondence with the ODL (step 420a), wherein the adjusting, by the first node and according to the adjustment requirement for the line interface rate, the transport bandwidth of the OCh link, adjusting the number of OTLs in the OTUCn link, and adjusting the number of ODLs in the ODUCn link comprises: in a case in which the line interface rate needs to be increased, increasing, by the first node, the transport bandwidth of the OCh link, adding j OTLs into the OTUCn link, and adding j ODLs into the ODUCn link, wherein j is a positive integer, wherein before the increasing, by the first node, the transport bandwidth of the OCh link, the method further comprises: sending, by the first node, first OCh protocol signaling and first optical signal configuration information to a second node, wherein the first OCh protocol signaling is used for requesting increasing the transport bandwidth of the OCh link, and the first optical signal configuration information is used for indicating a configuration of the optical signal; and receiving, by the first node, second OCh protocol signaling from the second node, wherein the second OCh protocol signaling is used for indicating that increasing the transport bandwidth of the OCh link is agreed. determining, by a first node, an adjustment requirement for a line interface rate (step 410a); and adjusting, by the first node and according to the adjustment requirement for the line interface rate, a transport bandwidth of an optical channel OCh link, adjusting the number of optical channel transport lanes OTLs in an optical channel transport unit OTUCn link, and adjusting the number of optical channel data lanes ODLs in an optical channel data unit ODUCn link, wherein the OTL is in one-to-one correspondence with the ODL (step 420a), wherein the adjusting, by the first node and according to the adjustment requirement for the line interface rate, the transport bandwidth of the OCh link, adjusting the number of OTLs in the OTUCn link, and adjusting the number of ODLs in the ODUCn link comprises: in a case in which the line interface rate needs to be increased, increasing, by the first node, the transport bandwidth of the OCh link, adding j OTLs into the OTUCn link, and adding j ODLs into the ODUCn link, wherein j is a positive integer, wherein before the increasing, by the first node, the transport bandwidth of the OCh link, the method further comprises: sending, by the first node, first OCh protocol signaling and first optical signal configuration information to a second node, wherein the first OCh protocol signaling is used for requesting increasing the transport bandwidth of the OCh link, and the first optical signal configuration information is used for indicating a configuration of the optical signal; and receiving, by the first node, second OCh protocol signaling from the second node, wherein the second OCh protocol signaling is used for indicating that increasing the transport bandwidth of the OCh link is agreed. in a case in which the line interface rate needs to be increased, increasing, by the first node, the transport bandwidth of the OCh link, adding j OTLs into the OTUCn link, and adding j ODLs into the ODUCn link, wherein j is a positive integer, wherein before the increasing, by the first node, the transport bandwidth of the OCh link, the method further comprises: sending, by the first node, first OCh protocol signaling and first optical signal configuration information to a second node, wherein the first OCh protocol signaling is used for requesting increasing the transport bandwidth of the OCh link, and the first optical signal configuration information is used for indicating a configuration of the optical signal; and receiving, by the first node, second OCh protocol signaling from the second node, wherein the second OCh protocol signaling is used for indicating that increasing the transport bandwidth of the OCh link is agreed. sending, by the first node, first OCh protocol signaling and first optical signal configuration information to a second node, wherein the first OCh protocol signaling is used for requesting increasing the transport bandwidth of the OCh link, and the first optical signal configuration information is used for indicating a configuration of the optical signal; and receiving, by the first node, second OCh protocol signaling from the second node, wherein the second OCh protocol signaling is used for indicating that increasing the transport bandwidth of the OCh link is agreed.