A data transmission method performed by a terminal for direct vehicle-to-X communication over a sidelink, characterized in that the method comprises: obtaining configuration information, wherein the configuration information comprises reliability information corresponding to a first identifier; obtaining to-be-transmitted data having a data attribute including reliability, wherein the reliability of the to-be-transmitted data is first reliability, wherein the first reliability reflects a transmission reliability requirement or level of the data or reflects an importance degree or importance level of the data; sending a sidelink buffer status report, BSR, to a network device if the first reliability of the to-be-transmitted data corresponds to the reliability information corresponding to the first identifier, wherein a first data field in the sidelink BSR is the first identifier; and wherein the reliability information comprises a first reliability threshold, and that the first reliability corresponds to the reliability information comprises: the first reliability is greater than or equal to the first reliability threshold; the reliability information comprises a second reliability threshold, and that the first reliability corresponds to the reliability information comprises: the first reliability is less than or equal to the second reliability threshold; the reliability information comprises a first reliability value set, and that the first reliability corresponds to the reliability information comprises: the first reliability is a member of the first reliability value set, wherein the first reliability value set is a group of discrete values; or the reliability information comprises a first reliability range, and that the first reliability corresponds to the reliability information comprises: the first reliability falls within the first reliability range. obtaining configuration information, wherein the configuration information comprises reliability information corresponding to a first identifier; obtaining to-be-transmitted data having a data attribute including reliability, wherein the reliability of the to-be-transmitted data is first reliability, wherein the first reliability reflects a transmission reliability requirement or level of the data or reflects an importance degree or importance level of the data; sending a sidelink buffer status report, BSR, to a network device if the first reliability of the to-be-transmitted data corresponds to the reliability information corresponding to the first identifier, wherein a first data field in the sidelink BSR is the first identifier; and wherein the reliability information comprises a first reliability threshold, and that the first reliability corresponds to the reliability information comprises: the first reliability is greater than or equal to the first reliability threshold; the reliability information comprises a second reliability threshold, and that the first reliability corresponds to the reliability information comprises: the first reliability is less than or equal to the second reliability threshold; the reliability information comprises a first reliability value set, and that the first reliability corresponds to the reliability information comprises: the first reliability is a member of the first reliability value set, wherein the first reliability value set is a group of discrete values; or the reliability information comprises a first reliability range, and that the first reliability corresponds to the reliability information comprises: the first reliability falls within the first reliability range.