Inclined hole forming of isolated pier pile has always been a construction difficulty problem in the open sea. This paper analyzes the construction difficulties and reasons of inclined rock-socketed piles concrete core such as drilling deviation，hole collapse and inefficiency during drilling construction in hard rock.Targeted measures are taken：selecting air lift reverse circulation rotary drilling machine and cone bit，assembleing the guide device in the middle of drill pipe，using sea water slurry supporting，reasonably adjusting the drilling pressure and drilling speed and other parameters，which successfully overcome the aforementioned difficulties. Thus the technology of rock socketed hole forming of offshore inclined pile is formed to provide reference for similar projects.