A novel energetic non-metallic pentazolate salt， 3，5-diamino-4-nitro-1H-pyrazol-2-ium pentazolate （3）， was synthesized by a metathesis reaction of 3，5-diamino-4-nitropyrazole hydrochloride with sodium pentazolate. The structure of 3 was characterized by nuclear magnetic resonance （NMR）， single crystal X-ray diffraction analysis （SC-XRD）， Fourier infrared spectroscopy （IR） and elemental analysis （EA）. The study on thermal behavior of 3 by using differential scanning calorimetry （DSC） and thermogravimetry （TG） show that its onset decomposition temperature is 119.5 ℃， which is higher than most non-metallic pentazolate salts. The apparent activation energies were calculated based on DSC curves at different heating rates. Based on the measured density at room temperature （1.71 g·cm^-3） and calculated enthalpy of formation （503.3 kJ·mol^-1）， the detonation performances of 3 （D=8483 m·s^-1， p=26.4 GPa） were calculated by Explo5 V6.05.02 software. The impact sensitivity and friction sensitivity of 3 are 10 J and 216 N， respectively.