The invention relates to the technical field of broadcast television and specifically to a device and method for synchronizing audio and video coding labial sound. The device comprises an audio and video signal input module, a video encoding module, an audio encoding module, a code stream output module, a system control module, a power module, an audio time delay module, and an audio and video synchronizing module. The system control module is electrically connected with the audio and video signal input module, the video encoding module, the audio encoding module, the code stream output module, the power module, the audio time delay module, and the audio and video synchronizing module. The audio time delay module is provided with a built-in FIFO buffer. The device is simple in structure, easy to use, achieves accurate audio and video labial sound synchronization by applying the audio time delay module and the audio and video synchronizing module to a conventional audio and video encoder, may stably perform synchronization even after long-time operation, satisfies the front-end broadcast demands of various levels of broadcast television networks, greatly increases work efficiency, and reduces operation cost.