The particle size and its distribution of metatitanic acid determines the particle size distribution and pigment properties of titanium dioxide pigment, it is great important to characterize the particle size distribution of metatitanic acid particles. Using metatitanic acid slurry hydrolyzed from industrial low concentration titanyl sulfate solution via short sulfate process as research object, the effects of dispersing media, dispersant and dispersing conditions on the particle size distribution by photon correlation spetroscopy were investigated. Proper dispersion media, dispersant and its concentration, ultrasonic vibration would all improve the Zeta potential of metatitanic acid particles, enhance the repulsion between particles and strengthen particle dispersion. The optimal dispersion conditions for metatitanic acid were slurry dosage of 0.044 g, 50 ml of 0.05% aqueous sodium hexametaphosphate solution, mechanical stirring time of 2 min, ultrasonic vibration time of 5 min. After thorough dispersion, the particle size distribution of metatitanic acid must be determined immediately.