Embodiments of the present invention provide a method and an apparatus for processing data. The method includes: performing code block segmentation on a data block to obtain multiple first blocks, wherein a difference between numbers of bits of any two first blocks in the multiple first blocks is not more than 1 bit; determining multiple second blocks according to a padding bit and the multiple first blocks, wherein a value of the padding bit is a preset value; adding consecutive N−K fixed bits to each of the multiple second blocks to obtain multiple third blocks, wherein a value of the fixed bit is a preset value, and N−K≧0; and performing polar encoding according to the multiple third blocks.