To analyze the vibration causes of a reservoir water conveyance culvert, the vibration characteristics of different positions of the culvert were monitored using a vibration monitor, and the source location of the vibration was preliminarily determined by analyzing the vibration variation law of different positions of the culvert. Then, a pipeline robot was used to examine the inside of the culvert, and the internal cause of the pipeline vibration was then analyzed based on the existing theory. Finally, the external causes of pipeline vibration were analyzed after the field excavation. The results show that the peak velocity, dominant frequency, peak acceleration and peak displacement of the particle at the position of gate valve are significantly greater than those at other measuring points. The vibration characteristics in front of and behind the gate valve are basically symmetrical, so it is speculated that the gate valve is the main vibration source. The vibration peak velocity, peak acceleration and peak displacement of the particle at the gate valve are vertical > tangential > radial, and the main vibration direction of the gate valve is vertical. The gate valve of water conveyance culvert can only be opened to no more than 1/3 of the designed maximum opening. When the gate valve opens at such a small opening, the vertical flow induced vibration is the main reason causing the vibration of the water conveyance culvert. The soil mass near the gate valve is loose, and there is no anchorage block to restrain the deformation of the culvert pipe, resulting in the vibration aggravation.