In addition to the traditional existed static model, the dynamic model is proposed to investigate the thickness (d) dependence of tribo-dielectric layer (TDL) with the device performance in the triboelectric nanogenerators (Tengs) in this work. With the involvement of one material parameter, i.e., electron-hole recombination rate (r) near the TDL in our developed dynamic model, the d dependence of TDL for the effective surface charge (Q s ) and output current (I) in the Tengs is derived. The maximum I (I max ) with the optimized TDL thickness (d max ) is further obtained with the consideration of different r. It can be found that the larger value of r in the material results in the smaller value of I max and the larger value of d max . At the same time, the theoretical dynamic model is compared with the experimental data. With the designed spin coating speed and time for the TDL deposition, the Tengs with different d is demonstrated and studied experimentally. The experimental data and the theoretical dynamic model agree very well with each other.