This paper analyzes the necessity of fast protection for capacitor bank with high specific storage used in SG-Ⅲ high power laser. A technical scheme with inductor and tailor-made fuse was proposed. Especially the design of fast protective fuse was introduced. The experiments demonstrated that the fast protective fuse can take action within a quarter of first cycle of current and limit the voltage reversal under 10%. The design of the protection can meet the project requirements and can reduce the damage of PPS to the lower extent and provent the personnel safe and collateral property from the all threats.