Recently, a new quench protection system using capacitor and switches has been announced to rapidly extract energy from high temperature superconducting (HTS) magnets. When a quench occurs, the quench protection system activates four MOSFET switches in sequence, and the energy stored in the magnet is extracted through an external resistor through a capacitor. In previous studies, the system was implemented for the protection of small-scale magnets, and the feasibility of the system was experimentally verified. The experimental results show that the energy extraction of the magnet is faster than the quench protection system using a conventional dump resistor. However, since proposed system is sensitive to capacitance, inductance, and four resistors, it is necessary to optimize design variables for various magnet systems. However, since the system is sensitive to capacitance, inductance, and four resistances, it is necessary to analyze and optimize the design parameters for various magnet systems. In this paper, the effect of each design variable on the protection performance is analyzed and a method for optimal design is presented. We also evaluated the performance by applying a design optimized for the scale-up test coil.