In view of the low drilling efficiency of elasticplastic dense mudstone in more than 400 meters of holes in north-situ leaching sandstone-type uranium deposits,research test was made on bit to improve the situation. Φ104 mm octagonal step rib bit was chosen for soft elastic-plastic dense smooth reddish brown and light green mudstone; Φ104 mm octagonal step rib bit was chosen for soft elastic-plastic dense gray mudstone; Φ104 mm staggered round flake PDC bit was chosen for brittle-plastic high dense black gray mudstone; Φ104 mm staggered round flake PDC bit was chosen for brittle-plastic high dense white mudstone; and Φ104 mm tooth shape PDC bit was chosen for hard-plastic high dense mudstone.