ε－HNIW samples were prepared by nitrolysis of two chemicals tetraacetyldiformylhexazaisowurzetane (TADFIW) and tetraacetyldibenzylhexazaisowurzetane(TADWBIW) respectively. Thermal decomposition parameters and impact sensitivity (H₅₀) of the two kinds of HNIW samples were determined and SEM photographs were given. The test results show that thermal decomposition parameters and impact sensitivity (H₅₀) of the two samples are almost same, which indicate these samples have the same chemico－physical properties and the different impurities contained in ε－HNIW samples mentioned above do not affect chemico－physical properties of these samples greatly.