In port,the ship waterline measurement by manpower read method is often employed to determine shipping capacity at hom e and abroad.Not only there is the risk,but also the measuring accuracy is lower .It has a broad prospect of applications in laser ranging field due to its high coherence,high monochromaticity,strong direction and high brightness.A new water level measuring system,using laser rangefinder sensor with phase method as lase r water level sensor without cooperative target,is presented.The laboratory and field experiments have been done to confirm the application field and measuring accuracy of the system.The results show that the measuring accuracy could reach ±1.5mm in calm water when the water turbidity value is greater than 300NTU.Fu rthermore,the measuring results disperse widely when the measuring period takes 1or 3min and the measuring accuracy can reach ±3mm for the measuring period of 5min in case of the water surface sloshing.The maximum measuring distance of the system could reach 12m.