A data sending method, comprising: producing, by a first forward error correction, FEC, unit of a sending device a first data stream on which first FEC encoding has been performed; producing, by a second FEC unit of the sending device a second data stream on which second FEC encoding has been performed; producing, by the first FEC unit, a third data stream on which third FEC encoding has been performed; and producing, by the second FEC unit, a fourth data stream on which fourth FEC encoding has been performed; interleaving, by an interleaving unit, the first data stream, the second data stream, the third data stream and the fourth data stream to obtain at least one output data stream; and transmitting the output data stream to a receiving device; wherein the step of interleaving specifically comprises: first interleaving, by the interleaving unit, the first FEC encoded data stream and the second FEC encoded data stream with each other; second interleaving, by the interleaving unit, the third FEC encoded data stream and the fourth FEC encoded data stream with each other; and third interleaving, by the interleaving unit, the data stream that is obtained by performing the first interleaving and the data stream that is obtained by performing the second interleaving, to obtain the output data stream; or, first interleaving, by the interleaving unit, the first FEC encoded data stream and the second FEC encoded data stream with each other; and second interleaving, by the interleaving unit, the third FEC encoded data stream and the fourth FEC encoded data stream with each other, wherein the resulting output data stream comprises a data stream that is obtained by performing the first interleaving and a data stream that is obtained by performing the second interleaving. producing, by a first forward error correction, FEC, unit of a sending device a first data stream on which first FEC encoding has been performed; producing, by a second FEC unit of the sending device a second data stream on which second FEC encoding has been performed; producing, by the first FEC unit, a third data stream on which third FEC encoding has been performed; and producing, by the second FEC unit, a fourth data stream on which fourth FEC encoding has been performed; interleaving, by an interleaving unit, the first data stream, the second data stream, the third data stream and the fourth data stream to obtain at least one output data stream; and transmitting the output data stream to a receiving device; wherein the step of interleaving specifically comprises: first interleaving, by the interleaving unit, the first FEC encoded data stream and the second FEC encoded data stream with each other; second interleaving, by the interleaving unit, the third FEC encoded data stream and the fourth FEC encoded data stream with each other; and third interleaving, by the interleaving unit, the data stream that is obtained by performing the first interleaving and the data stream that is obtained by performing the second interleaving, to obtain the output data stream; or, first interleaving, by the interleaving unit, the first FEC encoded data stream and the second FEC encoded data stream with each other; and second interleaving, by the interleaving unit, the third FEC encoded data stream and the fourth FEC encoded data stream with each other, wherein the resulting output data stream comprises a data stream that is obtained by performing the first interleaving and a data stream that is obtained by performing the second interleaving. first interleaving, by the interleaving unit, the first FEC encoded data stream and the second FEC encoded data stream with each other; second interleaving, by the interleaving unit, the third FEC encoded data stream and the fourth FEC encoded data stream with each other; and third interleaving, by the interleaving unit, the data stream that is obtained by performing the first interleaving and the data stream that is obtained by performing the second interleaving, to obtain the output data stream; or, first interleaving, by the interleaving unit, the first FEC encoded data stream and the second FEC encoded data stream with each other; and second interleaving, by the interleaving unit, the third FEC encoded data stream and the fourth FEC encoded data stream with each other, wherein the resulting output data stream comprises a data stream that is obtained by performing the first interleaving and a data stream that is obtained by performing the second interleaving.