To deal with the poor self-stability of loose formation and drill tools sticking caused by block-falling and hole shrinkage, new PDH-130 bidirectional rotary-percussion-extruding mole is designed by using the floating core tube to change impact piston stroke and achieve the reverse impact function when normal rotary-percussion-extruding drilling and drill pipe lifting are conducted. On the basis of the field tests, improvement is made on the structure of PDH-130 bidirectional impact mole to meet the construction requirements of rotary-percussion-extruding drilling in sand, gravel and other complex formations.