Downhole drill and shock absorber thereof

The invention discloses a shock absorber used for a downhole drill, which has a central through hole in axial direction thereof and comprises a first jointing disk connected with a knocker, a second jointing disk connected with a power head and a bolt assembly connecting the first jointing disk and the second jointing disk. Both the first jointing disk and the second jointing disk have coaxial blind holes of which the opening are on the connection face of the first jointing disk and the second jointing disk. A twist transmission pin of which the diameter is approximately identical with that of the blind hole is arranged inside the blind holes. The axial direction of the twist transmission pin is substantially parallel to that of the central through hole. The shock absorber can obviously decrease the load undertaken by the twist transmission element, improve durability and reliability thereof and obviously improve the reliability and stability of the downhole drill. The invention also discloses a downhole dril