Pentacyclo[5.4.0.0^{2, 6}.0^{3, 10}.0^{5, 9}]undecane(PCU) is a compound with potential application in high energy density caged hydrocarbon compounds. PCU as a high-energy additive can enhance the energy level of the liquid hydrocarbon fuel. The results show PCU has a combustion heat 44.5 MJ·kg^-1 and is insensitive to impact and friction. The physico-chemical properties of blending fuel which is composed of aviation kerosene RP-3 and PCU were studied. Results show that the saturated solution of mass fraction of PCU in kerosene RP-3 at 25 ℃ reaches 44.6%. When mass fraction of PCU in the blending fuel reaches 25%, in comparison with pure aviation kerosene RP-3, the density and volumetric heat content of the blending fuel increase by 7.8% and 9.5%, respectively, the flash point of the blending fuel increases from 48 ℃ to 49 ℃, and the freezing point of the blending fuel decreases from -59 ℃ to -62 ℃. The viscosity of the blending fuel at -40 ℃ is between 6.99 mm²·s^-1 and 13.64 mm²·s^-1. The blending fuel with 10% PCU can perform smooth ignition and stable combustion on a scram jet direct-connect test facility. PCU makes the supersonic combustion pressure of aviation kerosene RP-3 increase from 327 kPa to 339 kPa.