Dual-frequency aegon discharge at 100 m Torr is modeled with a 2-D fluid model in this study. The plate gap of the system is 20 mm, and discharges are modeled at High Frequency (HF) 40 MHz, 60 MHz, 80 MHz, Low Frequency (LF) 2 MHz, 5 MHz, 10 MHz, low-frequency voltage 50 V, 75 V, 100 V and high-frequency voltage 200 V, respectively. The spatial distribution of electron density and ion density and the periodic evolution of instantaneous electric potential in bulk plasma and sheath are discussed.The numerical results show that plasma density increases with HFs and LFs and LF voltage, while HFs has more effect on the density. It is concluded that improving the ratio of HFs/LFs and increasing LF voltages is a method to gain high density and high ion bombardment energy simultaneously based on the analysis of electric potential distribution.