The construction depth of steel pipe pile into deep soft rock is uncertain.Based on an actual project,a test study on the construction of steel pipe pile driving into deep soft rock is carried out by drivability analysis,full size pile driving test and bearing capacity test.The results show that for steel pipe pile into deep soft rock,the pile tip should adopt open form,so as to minimize the soil plug effect during the pile driving process and ensure the depth into soft rock.The soil plug effect coefficient during piling in mudstone can be smaller than that under static load condition,and the soil plug effect coefficient in argillaceous limestone can be referred to that under the static load condition,the soil plug coefficient for open-end steel pipe pile with diameter of 1,000 mm can be 0.45,and 0.33 for diameter of 1,200 mm.When the hammer energy is limited,the final hammering penetration of steel pipe pile into deep soft rock can be appropriately reduced compared with the final hammering penetration of conventional geology,and 1 mm per stroke can be used as the final penetration standard.