The(Y0.99Nd0.01)3Al5O12 nano-sized powders were synthesized by low temperature combustion (LCS), using Nd2O3, Y2O3, Al(NO3)3·9H2O, ammonia water and citric acid as starting materials. This method effectively solves the problems caused by solid-state reaction at high temperature and hard agglomerates brought by chemical precipitation method. The powders were characterized by TG-DTA, XRD,FT-IR and TEM, respectively. The crystallite sizes were calculated by Scherrer's formula using the full width at half maximum of YAG(420) diffraction lines. The study focused on the crystallization of ceramics with different heat treatment temperatures. The experiments show that the forming temperature of YAG crystal phase is 850 ℃ and YAP crystal phase appearing during the calcinations transforms to pure YAG at 1050 ℃. The particle size of the powders synthesized by LCS is in the range of 20～50 nm depending on the thermal treatment temperature. With the temperature increasing, the mean grain sizes ascend, the stand deviations keep at about 2.0 and crystal lattices decrease. The grains grows mainly by the grain boundary diffusion.The lattice parameter expansion is caused by an increase of repulsive dipolar interaction at the surface of particles.