The high surface area mesoporous SiO2 nanospheres （KCC-1） with fibrous and unique pore structure possess high specific surface area and abundant exposed active sites. KCC-1 is capable of effectively dispersing and stabilizing active components on surface, making an excellent carrier for loading active components. Nitrogen-doped porous carbon material was prepared via two-step pyrolysis using melamine with a high N atom content as carbon precursor. At the same time, the special fibrous structure of KCC-1 was utilized to disperse and confine the active component on its surface, and the effect of KCC-1 content on structure and electrochemical performance of porous carbon material was explored. The results indicate that the overall specific capacitance of material increases first and then decreases with the increase of KCC-1 content. When the mass ratio of KCC-1 is 6%, the specific capacitance of material is the highest, reaching 35.88 F·g-1 (at current density of 1 A·g-1), which representes an enhancement of approximately 588.7% compared with the pristine material without KCC-1. After conversion, the specific capacitance of active components at an equal mass can reach a maximum of 190.53 F·g-1. Therefore, this study demonstrates that the confinement effect of KCC-1 can effectively enhance electrochemical performance and utilization efficiency of active components, providing valuable references for its future application in supercapacitors.