In this paper,355nm laser induced damage threshold of the quartz glass was improved by HF acid treatment,optical transmissivity and damage threshold of quartz glass were improved by optimizing the HF concentration and acid etched time,which show that optical transmissivity and damage threshold were increased then decreased with the increase of the HF concentration and acid etched time.The experimental results show that the laser induced damage threshold of quartz glass at the experiment conditions of the 10% HF concentration and etched time 60 minutes is 15.17 J/cm2 and improves 167.5% compared to damage threshold before the acid treatment.The surface damage area change of quartz glass induced by the same 355nm laser energy density with/without HF acid etching was comparatively analyzed.Finally,the improvement mechanisms of 355nm laser induced damage threshold of quartz glass after the HF acid treatment are given.