The present disclosure relates to a communication method and system for converging a 5th-Generation (5G) communication system for supporting higher data rates beyond a 4th-Generation (4G) system with a technology for Internet of Things (IoT). The present disclosure may be applied to intelligent services based on the 5G communication technology and the IoT-related technology, such as smart home, smart building, smart city, smart car, connected car, health care, digital education, smart retail, security and safety services. The present invention provides a method and device for vehicle to everything (V2X) communications. The method comprises: receiving configuration signaling transmitted by an eNB, and then determining, according to the configuration signaling, at least one of a search space corresponding to S-DCI_C, a transmission carrier of S-DCI_C, and the number of bits corresponding to S-DCI_C; or determining, according to the configuration signaling, at least one optional time position information for transmitting a Side Link Synchronization Signal (SLSS) and a Physical Sidelink Broadcast CHannel (PSBCH), and then, based on coverage state about whether a first UE is within cellular network coverage, according to the type of a reference synchronization source, determining time position information from the at least one optional time position information for transmitting the SLSS and the PSBCH, identity information of the SLSS to be transmitted, and the value of the inCoverage field in the PSBCH to be transmitted. The present application also provides a transmitting and receiving method in V2X communication, comprising the steps of: detecting, by a first-type UE, a PSCCH in format of SCI X transmitted by other UEs, and determining, according to the SCI X, whether to further measure PSSCH-RSRP of a PSSCH scheduled by the SCI X and whether to further decode the PSSCH scheduled by the SCI X. The method provided by the present application further comprises the steps of: detecting, by a second-type UE, a PSCCH in format of SCI X transmitted by other UEs, and determining, according to a modulation and coding bit field in the SCI X and a predefined TBS mapping rule, a TBS of a PSSCH scheduled by the SCI X. The method provided by the present application further comprises the step of: determining, by the second-type UE and according to a modulation scheme, the transmitting power of the PSCCH of the SCI X and the transmitting power of the PSSCH scheduled by the SCI X. By the above method, the coexistence of a first-type V2X UE and a second-type V2X UE can be better realized, and the transmission efficiency of the second-type V2X UE can be improved.