A rotatable joint to carry high-pressure and low-pressure liquids to a workstation can include a housing, two connecting heads, a first connecting member, a second connecting member, and a rotation member. The housing defines a first connecting hole positioned along a center housing axis and a second connecting member spaced from the first connecting member and parallel to the housing axis. The first connecting member, the second connecting member, and the rotation member can be installed in the housing in that order. One connecting head communicates with the first connecting member, the second connecting member, and the rotation member in that order via the first connecting hole, and the other connecting head communicates with the first connecting member, the second connecting member, and the rotation member in that order, via the second connecting hole.