Proposed are a method and apparatus for receiving PPDU in a wireless LAN system. Specifically, a receiving STA receives a PPDU from a transmitting STA via broadband and decodes the PPDU. The broadband is a 320 MHz or 160+160 MHz bandwidth that is not preamble punctured. The PPDU includes a first field and a second field. The first field includes L-LTF. The PPDU includes a first signal field and a second signal field. The first field includes L-LTF. The first field is generated on the basis of one of a first, second, third or fourth phase rotation value. The first phase rotation value is a phase rotation value that obtains PAPR of the L-LTE optimized for the broadband on the basis of a first combination of RFs used for transmitting the PPDU. The first combination of RFs is a combination of 160 MHz-capable RFs or 320 MHz-capable RFs.