Abstract: By using the on-line particle state monitoring instrument,Spray watch 2i,the influence of the voltage,primary air pressure and spray distance on the temperature and velocity of the particles were studied. The resutts showed that the temperature and the velocity of the nano ceramic particles were significantly increased with the rise of the spraying voltage. Raising the pressure of the main gas,the temperature of the particles decreased,while the particle velocity increased. When the spraying distance was prolonged,the temperature and velocity of particles were simultaneously decreased.