An optical measurement method for the ultrasound field in water containing light scatterers is proposed. Using the proposed method, we can reconstruct the pressure field from the pressure gradient obtained by light deflection measurement based on the principle of the Shack–Hartmann wavefront sensor. The ultrasound field with and without light scatterers is measured by the proposed method and the measurement results are compared. The measurement results are almost the same regardless of the presence of light scatterers, and the robustness of the proposed method to light scatterers is confirmed.