The swelling of a dry cylindrical poly(acrylic acid-co-acrylamide) gel was observed in real time after immersed in water. Pattern formation was found during this process. The wetting process is divided into three stages: first, swelling in the radial direction with cusp-like patterns evolving on the surface; second, shrinking in the radial direction while swelling in the axial direction; the last one, re-swelling in the radial direction. The movement of the wetting front at the first stage exhibits Case II like diffusion of water in polymeric network.