Based on elasto-optic effect theory, we present a simplified model for the fiber squeezer assisted with a piezoceramic actuator (PZT), and it is experimentally demonstrated with reasonable approximation. Results show that there is a quadratic polynomial relationship between the arccosine reciprocal value of light intensity outputted from polarization analyzer and the reciprocal value of applied voltage for the PZT. Using this formula, the key parameters of the PZT such as the piezoelectric strain coefficient are further obtained. Our conclusions are significant for accurate measurement and polarization control.