Nanometer NiB amorphous alloy and nanometer NiB/Al composite were prepared by chemical reduction. XRD, TEM and SEM were used to analyze the crystal structure and microstructure of the nanometer catalysts. Results show that the nanometer NiB particles are amorphous alloy with 20-30 nm in diameter, and the nanometer NiB particles of the NiB/Al composite are coated on the Al particles uniformly and compactly in amorphous alloy form with 40-60 nm in diameter. The DTA results show that the amount of the catalysts has great catalysis effect on the thermal decomposition of ammonium perchlorate (AP). Based on the fitting results, the theory optimal amount of simplex nanometer NiB alloy and its composite are 8.91% and 7.93%, while the corresponding high temperature decomposition of AP can be decreased to 407.34 ℃ and 389.98 ℃, respectively. Furthermore, the NiB nanocomposite shows much better catalysis on AP/HTPB(hydroxyl-terminated polybutadiene)solid propellant thermal decomposition. The nanocomposite catalyst makes the high temperature decomposition of AP/HTPB propellant decreased by 12.2 ℃ lower than that of simplex nanometer NiB alloy,and the combination tendency of the thermal decomposition peaks of the propellant are much more obvious.