The dynamic slid process of soft fingertips on its object acts an important role in robotic grasping and in-hand manipulation. In order to study the deformation of the fingertip in this process, we regarded the soft fingertip as composed of a finite number of compressible and flexible cantilevers, and simulated the two-dimensional model of the soft fingertip, by focusing on the local displacement phenomenon and analyzing the sliding time sequence of the contacting point on the surface. We set up a finite element model for the sliding soft fingertip, and experimentally verified the local displacement change of the contact surface node when sliding occurs. Furthermore, a slip prediction method based on the position change pattern of the last sliding point under different initial normal grasping forces is proposed.