A method for transmitting a service flow from a transmitting end to a receiving end of a flexible Ethernet bundling group which comprises at least two physical layer modules, PHYs, wherein the transmitting end is configured to transmit at least one service flow using the bundling group, a bandwidth resource corresponding to the bundling group is divided into M timeslots, service data of the at least one service flow is encapsulated in N timeslots in the M timeslots, each timeslot in the N timeslots is mapped to one PHY in the bundling group, and service data encapsulated in a timeslot is transmitted by using a PHY to which the timeslot is mapped, wherein M is an integer greater than 1, and N is an integer greater than or equal to 1, and M ≥ N; and the method comprises: when a first PHY in the bundling group fails, determining, based on a preconfigured first timeslot configuration table, a target timeslot in the N timeslots that is mapped to the first PHY, wherein the first timeslot configuration table is used to indicate a mapping relationship between the M timeslots and PHYs in the bundling group; searching the M timeslots for an idle timeslot based on the first timeslot configuration table; adjusting the first timeslot configuration table when a quantity of idle timeslots in the M timeslots is greater than or equal to a quantity of target timeslots, so that all the N timeslots are mapped to other PHYs other than the first PHY in the bundling group, to obtain a second timeslot configuration table; and transmitting the at least one service flow based on the second timeslot configuration table by using the bundling group; wherein adjusting the first timeslot configuration table when the quantity of idle timeslots in the M timeslots is greater than or equal to the quantity of target timeslots comprises: selecting K idle timeslots from the M timeslots when the quantity of idle timeslots in the M timeslots is greater than or equal to the quantity of target timeslots, wherein K is equal to the quantity of target timeslots; and adjusting the first timeslot configuration table, so that a mapping relationship between the K idle timeslots and PHYs in the bundling group and a mapping relationship between the K target timeslots and PHYs in the bundling group are interchangeable. when a first PHY in the bundling group fails, determining, based on a preconfigured first timeslot configuration table, a target timeslot in the N timeslots that is mapped to the first PHY, wherein the first timeslot configuration table is used to indicate a mapping relationship between the M timeslots and PHYs in the bundling group; searching the M timeslots for an idle timeslot based on the first timeslot configuration table; adjusting the first timeslot configuration table when a quantity of idle timeslots in the M timeslots is greater than or equal to a quantity of target timeslots, so that all the N timeslots are mapped to other PHYs other than the first PHY in the bundling group, to obtain a second timeslot configuration table; and transmitting the at least one service flow based on the second timeslot configuration table by using the bundling group; wherein adjusting the first timeslot configuration table when the quantity of idle timeslots in the M timeslots is greater than or equal to the quantity of target timeslots comprises: selecting K idle timeslots from the M timeslots when the quantity of idle timeslots in the M timeslots is greater than or equal to the quantity of target timeslots, wherein K is equal to the quantity of target timeslots; and adjusting the first timeslot configuration table, so that a mapping relationship between the K idle timeslots and PHYs in the bundling group and a mapping relationship between the K target timeslots and PHYs in the bundling group are interchangeable. selecting K idle timeslots from the M timeslots when the quantity of idle timeslots in the M timeslots is greater than or equal to the quantity of target timeslots, wherein K is equal to the quantity of target timeslots; and adjusting the first timeslot configuration table, so that a mapping relationship between the K idle timeslots and PHYs in the bundling group and a mapping relationship between the K target timeslots and PHYs in the bundling group are interchangeable.