To study the effect of composite emulsifiers on the thermal decomposition characteristics and detonation velocity of heavy ammonium nitrate-fuel oil (HANFO) emulsion matrices, the thermal decomposition process of the emulsion matrices prepared by five different composite emulsifiers was studied by thermogravimetry-differential thermogravimetry (TG-DTG) under four heating rates. The thermodynamic parameters such as activation energy and pre-exponential factor of the five emulsion matrices were calculated by the Ozawa method and the Kissinger method, and the mechanism function was solved by the Satava-Sestak method. The detonation velocity of HANFO emulsion matrices was measured using a discrete-point electric method. The results showed that the decomposition onset temperature of the HANFO emulsion matrix first increased and then decreased with the addition of emulsifier T152. The emulsion matrix with a Span80 : T152 ratio of 1 : 2 exhibited the highest decomposition onset temperature of 171 degrees C. Among the five samples, sample 4 had the highest activation energy (108.71 kJ mol(-1)), indicating that the thermal stability of sample 4 was greater than those of the other four samples. The detonation velocity test results revealed that the composite emulsifier strongly affected the detonation performance of HANFO. The sample with a Span-80 : T-152 ratio of 1 : 2 had a higher detonation velocity than the other four samples.