The relationship between the changes of Tongguan elevation and the sediment deposition in the lower reaches of Weihe river since the establishment of Sanmenxia reservoir indicates that: there was a declining trend in tongguan elevation since the flood season in 2002, the elevation of tongguan was 327.63 m after the flood season in 2015, it was still on the high side. Tongguan elevation changes are closely associated with the sediment deposition in lower reaches of Weihe river, the deposition caused by the beach groove profile adjustment under the lifting of Tongguan elevation accounts for about 78.3% of sedimentation in the lower reaches of Weihe river from 1971 to 2003, this was the most important influencing factors for serious silting in lower reaches of Weihe river. The correlation between tongguan elevation and accumulative deposition in the lower reaches of Weihe river was obviously weak from 2003 to 2015. However, the amount of sediment deposition in the lower reaches of Weihe was still significantly increased or decreased with the increase or decrease of Tongguan elevation. Massive deposition had gradually evolved into the ground “suspended river” in the lower reaches of the Weihe River. It fundamentally changed the situation of flood control and drainage at Weihe River downstream, and had a serious impact on the regional economic and social development. Comprehensive measures should be taken to control the Tongguan elevation below the level of 325.60-325.69 m, which aims to reduce the sediment deposition, improve the conditions of river flood, decrease the coastal flood disaster risk, and provide a safe environment for the regional development.