Drilling Jar Type BZ is full mechanical type drilling jar and releasing stuck tool. The Drilling Jar integrates the upward jarring with the downward jarring so that it can release from the tight pull or the sticking etc. during drilling. The load（jarring force）scope of the upward jarring and the downward jarring is so wide that it can be adjusted in the maintenance station or in the well site according to the requirement. The special flexible joint can reduce the flexural stress of the drilling jar body efficiently. So it is the first selected drilling jar for vertical well, deep sell, directional well and complicated well operations.