The Qingshan Junction of the Lishui River confronts some flow problems in the upstream entrance area，such as meandering rivers，the topography of bifurcated channels，sudden expansion and reduction of flow sections，and flow rates. This study uses the fixed-bed physical model to study the improvement in flow conditions in the upstream entrance area and the influencing factors and proposes optimization measures to improve flow conditions. The results reveal that the navigable flow conditions cannot be satisfied under the design scheme and Scheme 1 for the improvement to the upstream entrance area. According to the arrangement of Scheme 2，when three current diversion piers are arranged in the upstream entrance area in a non-staggered manner，and the right bifurcated diversion is dredged up to 43.0 m，the flow conditions of the upstream entrance area can be better improved，and the flow conditions in the entrance area of the ship lock under the design navigable water level can meet the requirements of safe navigation of ships.