Abstract: IsoTruss is a new ultra-lightweight composite structure, combining the advantage of lightweight material and structure. The structural features of IsoTruss were analyzed and the manufacturing process was summarized in this paper. Based on the structural features of IsoTruss, a flexible mandrel was designed and manufactured. 8-node single IsoTruss specimens were filament wound using the flexible mandrel and IsoTruss members were consolidated with aramid fiber. The compression test, bending test and torsion test were carried out to evaluate mechanical properties of IsoTruss specimens. The results of the compression test show that the average stiffness-to-mass ratio is 1 944.8 (kN/mm)/kg, and the average strength-to-mass ratio is 833.8 kN/kg, which achieve the performance of this type of composite structures and are higher than composite grid structures. Furthermore, the test results also indicate that the flexible mandrel, cooperated with consolidation using aramid fibre, can fabricate IsoTruss structures with high mechanical properties.