Abstract: The analysis of vessel attitude and the effect of vessel attitude for multibeam echo sounding are discussed in this paper.During analyzing the factors that affect vessel attitude,wind power,wind direction,current velocity,water depth,vessel velocity are thought to be external factors.The yawing angle is looked as summary effect of wind power,wind direction,current velocity,water depth for vessel attitude.Yawing angle,cross wave,water depth and the shape of sea bed(or river bed) are included in effect factors for vessel roll.The disturbed factors for dynamic squat includes mainly vessel velocity,yawing angle and coefficient of vessel shape.In these factors,vessel velocity is looked as a key factor.The effect factors for pitch is similar to dynamic squat situation,and the effect of vessel velocity is direct.In general,all of these factors for roll is larger than for pitch. With the change of vessel attitude,the transducer of multibeam echo sounder is changed.The change is produced by roll,pitch and heading,so the change must affect the coordinate of beam footprint coordinate.In this paper,the solving method used to get attitude effect and effect of attitude error for coordinate is given.By calculating and comparing,some analyses and researches are done in this paper,and we get some conclusions.It accords with practical surveying.