Abstract: To achieve high-precision three-dimensional speed measurement of large-scale underwater volume targets, this paper proposes a volume target speed measurement method. Based on the traditional particle model, this method introduces the target attitude and the installation position of the measurement transducer, and considers the spatial position relationship between the observed position and the position to be measured, so as to construct a three-dimensional velocity solution model. In typical application scenarios involving vertically moving targets, theoretical analysis and numerical simulation results indicate that the model error of traditional methods is primarily concentrated in the vertical direction and is closely related to parameters such as the position, radius, and speed of the target. The proposed method effectively eliminates the model error caused by the inconsistency between the observed position and the position to be measured. In the integrated error simulation scenario of long baseline base station position error of 0.3 m and radial velocity element error of 0.2 m/s, the velocity measurement error is reduced from the traditional method of 10.8 m /s to 0.7 m /s.