Abstract: Spraying of liquid-solid suspension is a common phenomenon in removal of sulfuroxide from flue gas,in prevention of gas explosion by water droplets in coal mine and in coal slurry spray burning. Pressure-spray nozzle is generally used due to its simple structure and convenience for application.Spraying of the suspension is made by the vibration wave from pressure which disturbs the unstable fluid membrane and the force of inertia of mini-particales. The factors that affect the spray is analyzed, and a mathematical model is set forth.The spray droplet diameter d₃₂ is a function of independent variables of suspension pressure, mini-particle diameter, density and sold content.Spray droplet diameter d₃₂ is decreasing then increasing with suspension pressure and mini-particle density,which d₃₂ is increasing monotonously with mini-particles diameter and solid content in suspension.