A safe and reliable built-in hanging hammer of simple structure is developed， which solves the problem that the hanging hammer cannot be applied in power head drilling rig due to space limitation. The design idea， structure principle， operation method， precautions for safe operation and field application are introduced. The practice shows that the tool can effectively deal with the casing or drill pipe stuck or buried in the upper hole and also can cooperate with other tools to deal with the casing or drill pipe stuck or buried in the bottom hole. The tool is not only suitable for power head core drill， but also for vertical-type drilling rig. Since applied by our company in 2017， the tool has successfully dealt with more than 600 meters of stuck casings or drill pipes， which produces a marked effect. The tool provides a new solution for handling the stuck wireline core drilling tool used in the power head core drill， especially provides a useful supplement for portable drilling rig to paly a role in green exploration.