The eutectic mixtures of 2，4，6-trinitro-3-bromoanisole （TNBA） and 1，3，3-trinitroazetidine （TNAZ） with different mass ratios were prepared by the electrostatic spray method. T-X and H-X phase diagrams were drawn according to the differential scanning calorimetry （DSC） curves of the eutectic mixtures to obtain the mass ratio of the lowest eutectic. Scanning Electron Microscopy （SEM）， Energy Dispersive Spectroscopy （EDS）， High Performance Liquid Chromatography （HPLC）， X-ray Powder Diffraction （XRD）， Infrared （IR）， X-ray Photoelectron Spectroscopy （XPS）， DSC， and thermogravimetry-mass （TG-MS） spectrometry were used to determine the morphology， component content， element distribution， crystal structure and thermal decomposition properties of the lowest eutectic. And the mechanical sensitivity， thermal sensitivity and detonation performances of the lowest eutectic were tested and theoretically calculated. The results showed that 60.95∶39.05 is the optimal mass ratio of TNBA/TNAZ lowest eutectic mixture； the microscopic morphology has no sharp edges and corners； the component proportion is the same as before electrostatic spraying； the surface elements are evenly distributed； and the crystal structure is basically the same as that of the raw materials. The eutectic temperature is 350.18 K， which is 22.72 K and 24.82 K lower than that of raw materials TNBA and TNAZ. The thermal decomposition reaction rate constant （k）， activation enthalpy （ΔH^≠）， activation energy （E_K）， activated Gibbs free energy （ΔG^≠）， and activation entropy （ΔS^≠） of the lowest eutectic are 0.33 s^-1， 60.10 kJ·mol^-1， 64.44 kJ·mol^-1， 135.21 kJ·mol^-1， and -143.78 J·（mol∙K）^-1， respectively. The impact sensitivity （H₅₀）， friction sensitivity （FS）， and 5s explosion temperature of the lowest eutectic mixture are 42 cm， 20%， and 558 K， respectively. Its detonation performance （OB=-34.83%，Q=5101.78 kJ·kg^-1，V_D=7598.37 m·s^-1） is between TNBA and TNAZ. The main detonation products are N₂、C（d）、CO、CO₂ and H₂O.