Slurry circulating system for cast-in-situ bored pile in offshore area and construction method of slurry circulating system

The invention relates to the technical field of civil construction, and particularly discloses a mud circulating system for a cast-in-situ bored pile in an offshore area and a construction method of the mud circulating system. The mud circulating system comprises a mud pool, a waste mud treatment pool, a mud conveying pipeline, a mud purifier and a drilling slag box; the inlet end of the slurry purifier is communicated with a slurry pump of the drilling machine, the first outlet end is communicated with the slurry pond through a pipeline, the second outlet end is communicated with the drilling slag box, and the slurry pond and the waste slurry treatment pond are both arranged on the bank of a steel trestle bridge head and separated from a construction trestle steel platform; the system further comprises a mud performance detection instrument which is arranged at the mud pool and used for detecting the mud performance at the inlet position of the mud conveying pipeline. The mud pool, the waste mud treatment po