To reduce the mechanical sensitivity of ultra-fine ammonium perchlorate (AP),a surface modification of ultra-fine AP was performed by jet mill and the ultra-fine AP composite particles,including ultra-fine AP/nano-graphite(AP-1),ultra-fine AP/graphite(AP-2),ultra-fine AP/carbon black(AP-3) and blank ultra-fine AP comparison sample(AP-C),which were prepared using nano-graphite,graphite and carbon black as insensitive modifier. The morphology and structure of the composite particles were characterized by field emission scanning electron microscopy (SEM),micro particle size instrument,X-ray powder diffraction (XRD) and Fourier transform infrared spectrometer (FTIR). The mechanical sensitivity of ultra-fine AP before and after composition was tested by impact sensitivity instrument and friction sensitivity instrument. Thermal decomposition performance of the composite particles was investigated by differential scanning calorimeter (DSC). Results show that compared with the AP-C,the impact sensitivities of AP-1,AP-2 and AP-3 decrease by 18.2%,21.2% and 8.9%,respectively,and the friction sensitivities of AP-1,AP-2 and AP-3 decrease by 12.5%,12.5% and 8.3%,respectively,and the high temperature decomposition peak at a heating rate of 10 ℃·min^-1 of AP-1,AP-2 and AP-3 shifs 75.4,64.2 ℃ and 44.5 ℃ downwards,respectively.