<p>The penetration of sampling tubes is a primary source of sampling disturbance, affecting the quality of undisturbed soil samples and the reliability of subsequent laboratory test results. To investigate the patterns of soil disturbance and deformation during sampling tube penetration and their influencing factors, a visualization test apparatus for sampling tube penetration was developed using Particle Image Velocimetry (PIV) technology. Penetration tests were conducted in sands with different sampling tube diameters and wall thicknesses, revealing the distribution characteristics of soil disturbance deformation during penetration. The results indicate that the soil inside the tube consistently exhibits a three-stage deformation sequence—compression, heave, and re-compression—throughout penetration, independent of sampler geometry. In the heaving zone, disturbance deformation reaches its maximum at the tube axis and decreases toward the tube wall, while in the compressive zone, disturbance deformation is minimal at the tube axis and gradually increases toward the tube wall. The tube diameter exerts a dominant control on the spatial pattern of disturbance, while wall thickness mainly affects its magnitude.</p>