Bored pile technology is a common method of foundation reinforcement.How to effectively control the stability of bored piles after drilling is very important to ensure the integral quality of bored piles.Taking a project in coastal area as an example，aiming at the problems of low hole-forming efficiency and soil gushing at the bottom of the hole encountered in the construction of long spiral bored pile in water-rich sandy soil layer,the construction method of synchronous water-filling at the bottom of the hole after drilling is put forward and is verified by pile test.The result shows that water injection at the bottom of the hole can effectively solve the problem of soil gushing at the bottom of the hole after drilling.Using the bottom water injection technology of long screw bored pile can not only reduce the cost of construction,but also ensure the quality of construction and give full play to the characteristics of high construction efficiency of long screw drilling rig,therefore have good practicability.