Abstract: The high purity quartz was prepared using mixed acid at thermal pressure leaching.The influential factors such as concentration of HF,HCl and HNO_3, liquid-solid ratio,reaction time and temperature on purification of vein quartz as thermal pressure leaching were investigated.The results showed that the rate of removal of impurity metal elements Fe,Al,Ca,Mg,K,Na were respectively 67.04%,96.96%,84.97%,73.18%,76.25%,and 58.97% at the optimizational process parameters.During this thermal pressure leaching,the mixed acid could not only be reacted with impurity mineral on the surface of quartz particles,but also be diffused into the interface or inside along the crack of quartz crystal particles.It will be lattice distorted owing to the part of interstitial atoms dissolved out and resulting that the silicon oxygen tetrahedral arrangement the transition from the rule to the irregular in the crystals of quartz which increasing the probability of the dissolution of the metal atom and in favor of quartz purification.