The current standards in vehicle-to-everything (V2X) communication technology still have some problems, such as unclear technical requirement details. Consequently, the terminal products of V2X communication are different from each other, and the communication protocol stacks cannot be fully interconnected. To solve this problem, we analyze the performance requirements and overall layering status of an LTE-V2X protocol stack, propose a software and hardware solution for it, and improve the design details of each layer. Then, we complete the filling, encoding, and decoding of the message data, construct the data frames of each layer, and design a layer-by-layer encapsulation mechanism. On this basis, the communication performance of the protocol stack is tested in a real road scene, and the test results show that the protocol stack meets the design requirements and the top application specification on the protocol stack.