ICPF (Ionic Conducting Polymer Film) is a kind of smart film and has the characteristics of flexibility, good response and being driven by a low voltage. In order to illuminate the deformation dynamics of ICPF, the curvature of a thin strip ICPF under stepwise application of electric field is formulated according to Flory’s gel swell theory. The interplay mechanism of the deformation of gel, permeation of water and the transport of ions is described. A novel fish-like flexible micro-robot whose tail is actuated by ICPF is presented. According to the Pseudo-Rigid-Body-Dynamic-Model (PRBDM) the frequency analysis of the micro-robot is investigated, and then, the relation between the structure parameters and the natural frequency of the tail is theoretically derived and some analysis and experiment graphs about the angle displacement of the tail are performed.