The present disclosure provides an annular anchor, a method for calculating antitorque bearing strength thereof and an installing and recycling assemble for the anchor, relating to the technical field of ocean engineering. The annular anchor includes an anchor body opened at its upper and lower ends, and a connection portion arranged on the outer side wall of said anchor body for connecting with parts to be moored. The annular anchor provided by the present disclosure omits the top cover as the structure prevailing in the traditional suction anchor, avoiding the drawback of installing the traditional suction anchor on the seabed, instead the annular anchor can be installed to a certain depth below the seabed. During the descent, there is no need to take into account the resistance caused by the top cover, so that the annular anchor can be installed simply and quickly.