Optimal synthesis parameters of YBaCo4O7 had been done. The X-ray diffraction (XRD) results show that YBaCo4O7 samples are all single phase. The Scanning electron microscope (SEM) results indicate that with increasing calcination temperature, calcination time, and decreasing cooling rate, grain transformed from porous agglomerates of sphere or sphere-like to agglomerates of irregular polyhedron, as well as the grain size increased. YBaCo4O7+ with oxygen storage capacity of 102.52 wt.%, maximum rate of intaking oxygen temperature of 339.7 degrees C, and maximum rate of releasing oxygen temperature of 369.8 degrees C can be obtained by the optimal synthesis parameters, calcination temperature of 1100 degrees C, calcination time of 30 h, air-cooling, and solid-state reaction method.