Abstract: Structures of cantilevers of jack-up drilling platforms is discussed and characteristics of various structures of the cantilever beam are analyzed. Traditional cantilever is applied widely and manufacturing technologies are not high. XY-cantilever beams have compact structure arrangements and large coverage. But it is patented worldwide and is very expensive. Rotating cantilever and improved cantilever are not widely used because of their complicated structures and its high request for moving rail or sliding shoe. Comparison is made among the three types of skidding of the traditional cantilever base-pawl movement, pin roll movement and gear-rack movement. Among them, pin roll movement is adopted widely because of its simple structure and convenient function implementation. The type selection of present jack-up drilling platforms is discussed.