The invention relates to a maritime waterproof conduit piling cap device. The maritime waterproof conduit piling cap device is characterized by comprising an outer sleeve with the top end sealed and the bottom end open, an inner sleeve and a plurality of inner wings, wherein one top end of the inner sleeve is fixed on the sealed surface of the top end of the outer sleeve and the bottom end of the inner sleeve is open; and the plurality of inner wings are fixed on an inner barrel wall of the inner sleeve. The bottom end of the outer sleeve is in a horn opening shape. An annular gap is formed between an inner barrel wall of the outer sleeve and an outer barrel wall of the inner sleeve. The size of the annular gap is slightly larger than the wall thickness of a waterproof conduit. The thickness of every inner wing is equal to the wall thickness of the waterproof conduit. The maritime waterproof conduit piling cap device can be widely applied to maritime petroleum drilling and other offshore engineering piling operations.