A three-dimensional acoustic vector field model was developed using Gaussian beam tracing. The field at any location is computed by coherently summing all contributing beams, where the beam equation of particle velocity depends only on beam width and eikonal. A deep-sea long-range sound propagation experiment in the South China Sea was analyzed using vector hydrophone measurements of particle velocity and sound pressure. The results were compared with the model predictions, indicating that beam tracing is effective in predicting sound pressure and acoustic vector fields in deep water.