Aiming to address the operation stability affected by the parameter time-variation of the ultrasonic motor and the harmonic effect of the drive voltage，this paper focuses on the design and optimization of LLCC resonant network topology as well as total harmonic distortion （THD） of the output voltage for driving linear ultrasonic motors （LUMs）. Such method can effectively overcome the issue on the variations of the driving voltages caused by the parameter time-variation to improve their operation stability. Firstly，the calculation method for the LLCC matching parameters is derived by using a contact-based equivalent circuit of LUMs considering the stator/mover contact boundary conditions，and a compensation capacitor is added to improve the elasticity margin and the stability of impedance matching. Furthermore，the filtering characteristics of the LLCC resonant network near the resonant frequency is discussed in depth，and the mathematical relationships are derived between the THD of the output voltage and the parameters of the LLCC resonant network are derived. Furthermore，the influence of the parasitic parameters of the transformer on the LLCC resonant network is also analyzed. On this basis，the design optimization methodology for the LLCC resonant network is proposed while acting the THD of the sinusoidal output voltage as the main target. Finally，a LLCC resonant driver is designed for a V-shape LUM，and the corresponding experiments are conducted. The results indicated that the gain and the THD of the output voltage as well as the peak amplitude of the series capacitor voltage itself are determined by the ratio of the series capacitor and the parallel capacitor in the resonant network. The series inductor is the dominating factor for the soft switching characteristics. The THD of the output voltage is controlled below 3%，which is improved more than 70% compared to the unoptimized LLCC resonant driver.