In the paper, the determination of the minimum cover thickness of Yingpanlu Xiangjiang River Crossing Tunnel in Changsha is studied, so as to ensure the traffic functions of the tunnel and to achieve smooth connection between the underwater tunnel and the ground surface roads. The existing method at home and abroad to determine the minimum cover thickness of underwater tunnels are discussed, and a more economic and rational minimum cover thickness determination method is proposed for the tunnel. According to the method proposed, the magnitude of the construction risks is determined based on the engineering measures taken and by means of risk analysis, numerical calculation, monitoring and measurement, and the minimum cover thickness of the tunnel is optimized by considering the traffic functions, economic analysis results and social significance. Finally, the method proposed is summarized. 