In this work, high-density jet fuel range cycloalkanes were synthesized in high yields (similar to 80%) by solvent-free aldol condensation of cyclopentanone and furfural followed by hydrodeoxygenation (HDO). Sodium-promoted magnesium-aluminum mixed oxides (Na-MgAlO) exhibited a high catalytic activity in the aldol condensation of cyclopentanone and furfural under a solvent-free condition. Furfural conversion of 99.4% with almost 100% selectivity for 2-(2-furylmethylidene) cyclopentanone and 2,5-bis(2-furylmethylidene) cyclopentanone were obtained over the 5.7%Na-MgAlO catalyst under mild conditions (80 degrees C, 2 h). The Na-MgAlO catalysts were characterized by multiple technologies, such as N-2 physisorption, powder X-ray diffraction, Fourier transform infrared spectra, and CO2 temperature-programmed desorption, and so on. It was found that the high catalytic activity for aldol condensation of cyclopentanone and furfural was clearly related to the amount and strength of basicity of Na-MgAlO catalysts. Finally, the condensation products were converted to jet fuel range cycloalkanes by HDO over Pd/C and HZSM-5 catalysts. The density, heating value, and freezing point of the HDO liquid products were 0.83 g/cm(3), 43.1 MJ/Kg, and -27.7 degrees C, respectively. The results suggest that these cycloalkanes are promising as blending components for jet fuel.