A method and an apparatus for processing data of multiple rates, where the method includes receiving, by a data processing apparatus, first data whose transmission rate is a first rate and second data whose transmission rate is a second rate, obtaining, by the data processing apparatus, N1 pieces of third data and N2 pieces of fourth data according to the first data, obtaining, by the data processing apparatus, M1 pieces of fifth data and M2 pieces of sixth data according to the second data, obtaining, by the data processing apparatus, serial seventh data according to the N1 pieces of third data, the N2 pieces of fourth data, and a first modulation scheme, and obtaining, by the data processing apparatus, serial eighth data according to the M1 pieces of fifth data, the M2 pieces of sixth data, and a second modulation scheme.