The formation conditions of Wenchuan earthquake fault scientific drilling project are very complicated. Broken rock formation, lost circulation and borehole shrinkage are encountered frequently. As a result, many drilling accidents, such as drill pipe sticking， drilling pipe breaking, objects dropping and so on happened and were successfully solved. Technical measures for preventing accidents, including scientific diagnosis and optimizing drilling method, drill tool structure and drilling mud system, have been taken to minimize accidents and ensure the smooth progress of scientific drilling project.