Composite cross arm is usually arranged into a fully constrained or free rotating type，the former is very expensive， while the latter results in the difficulties of operation and maintenance due to irregular rotation of the cross arm． In order to eliminate the shortcomings of the traditional design，the controllable rotating "V" series scheme is put forward，that is，while all of the cross arms can be constrained in normal operation，some of the cross arms can be constrained in non － uniform ice conditions，and all of them can freely rotate in wire breakage situation． With similar cost，the "V" series scheme includes all the advantages of fully constrained scheme and freely rotating scheme． Through the improvement of the traditional schemes， the structure arrangement，the working mode and the load value principle of the new type " V" series controllable rotating scheme are determined，which can provide a simple and feasible operation suggestion for the proposed scheme．