A method (200) or device for integrity protection of sidelink communication or Uu interface communication, which can achieve the integrity protection of a PDCP layer, thereby improving the security of communication. The method (200) comprises: obtaining a first BEARER parameter value on the basis of at least one of the following: a logical channel identifier (LCID) corresponding to data transmitted in sidelink communication, an access communication standard used by the sidelink communication, a BEARER parameter value allocated for the sidelink communication, and a preset BEARER parameter value, wherein the bit length of the LCID corresponding to the transmitted data is greater than the bit length of the first BEARER parameter value (210); and calculating an integrity message authentication code MAC-I or a desired integrity message authentication code XMAC-I for the sidelink communication on the basis of the first BEARER parameter value (220).