The invention relates to a compact periclase chondrule and a preparing method thereof. According to a technical scheme, magnesium hydroxide powder is put into a material barrel of a granulating device; water accounting for 5-30 wt% of the magnesium hydroxide powder is added into the material barrel with the speed being 1000-3000 r/min; when a spherical particle is generated, the rotating speed is adjusted to 500-1000 r/min, and granulation is stopped after 1-10 min of running to obtain a magnesium hydroxide spherical particle; the magnesium hydroxide spherical particle is taken out and dried at 110 DEG C for 24 h; and then the dried magnesium hydroxide spherical particle is put into a heating kiln, the temperature is maintained at 1400-1700 DEG C for 1-6 h, and the spherical particle is cooled to obtain the compact periclase chondrule. The compact periclase chondrule and the method have characteristics of a simple process and a low cost. The using temperature of the prepared compact periclase chondrule is high, the high-temperature performance stability and hydration resistance of the prepared compact periclase chondrule are good, and the compact periclase chondrule is an excellent raw material for preparing magnesium refractory materials and high-temperature ceramics, particularly magnesium unshaped refractory materials.