Proposed are a method and apparatus for receiving a PPDU on which BCC interleaving has been performed in a Multi-RU in a wireless LAN system. Specifically, a reception STA receives, from a transmission STA, a PPDU comprising a data field and decodes the data field. The data field is received via a Multi-RU which is an aggregate of a first RU and a second RU. The data field is generated on the basis of a coded bit string included in a BCC interleaver block. The coded bit string is obtained by interleaving a data bit string on the basis of first and second parameters. The data bit string is interleaved as the data bit string is entered into the BCC interleaver block in rows on the basis of the first parameter and is read out in columns of the BCC interleaver block on the basis of the second parameter.