To improve the compatibility of dihydroxylammonium 5，5′-bitetrazole-1，1′-diolate（TKX-50） with nitrocellulose（NC）， silane coupling agent （KH550） was used as the coating agent and three TKX-50/KH550 composites （TK1， TK2， TK3） were obtained.The morphology， structure and thermal stability of the composites were studied by using scanning electron microscopy （SEM）， Fourier infrared spectroscopy （FTIR）， and differential scanning calorimetry （DSC）. Accelerating rate calorimeter （ARC） and DSC were used to examine the compatibility of TKX-50/KH550 composites with NC. The results show that the apparent activation energy of thermal decomposition of the prepared TKX-50/KH550 composites are 190.03， 195.82 and 194.42 kJ·mol^-1 respectively higher than that of TKX-50 （138.86 kJ·mol^-1）， indicating the thermal stability of TKX-50 is improved by KH550 coating. In adiabatic conditions， the initial thermal decomposition temperature of the mixtures of TKX-50/KH550 composites and NC are 14.93， 18.18 and 17.90 ℃ respectively higher than that of TKX-50 and NC. After coated with KH550， the compatibility of TKX-50 and NC is improved， and the compatibility level of TKX-50/KH550 composites and NC is raised from Level 3 to Level 2.