Plasma immersion ion implantation (PIII) of polymer materials is inherently difficult because the voltage across the sheath is reduced by the voltage drop across the insulator due to dielectric capacitance and charge accumulating on the insulator surface. The spatiotemporal evolutions of plasma sheath, energy and dose of ions are simulated by particle-in-cell (PIC) model for ion implantation into insulator materials. Statistical results can be achieved through scouting each ion motion in the plasma sheath. Based on the PIC model, the secondary electron emission (SEE) coefficient is determined according to the instant energy of implanting ions. Effects of thickness, dielectric constant and SEE coefficient on sheath evolution, dose and energy of incident ions are studied. The ion implantation doses and the share of high-energy incident ions are basically equivalent to the case of implantation of conductor ions, when the polymer thickness is less than 200 m, relative dielectric constant is more than 7, and SEE coefficient is less than 0.5. The numerical simulation of ion implantation into polymer can effectively provide a scientific and experimental basis for PIII of insulators and semiconductors.