Abstract We performed a comprehensive investigation of the relationship between the maximum operating frequency of the NbN superconducting frequency divider and the key parameters of the NbN Josephson junction (JJ). We designed a superconducting frequency divider that uses a single NbN JJ as a pulse generator, several NbN Josephson transmission lines, an NbN Toggle Flip-flop, and a load. By comparing the bias voltage V _in of the pulse generator with the output voltage V _out of the load, we determined if the circuit was working correctly and calculated the maximum operating frequency f _max. Additionally, we employed JSICsim software for simulations to analyze the impact of key parameters of the NbN JJ, such as critical current density J _c, gap voltage V _g, characteristic voltage V _c, quality factor Q, and specific capacitance C _s, on f _max. The simulation results demonstrate that f _max increases with increasing J _c and Q. Specifically when J _c exceeds 300 kA cm⁻² and Q surpasses 4, the superconducting frequency divider can achieve a f _max of 1 THz. Furthermore, we successfully fabricated a superconducting frequency divider using a 10 kA cm⁻² process and tested a f _max of 260 GHz, with a deviation of approximately 6% from the simulation results.