Auxiliary arm, arm support assembly and crane

The invention relates to the field of crane structures, and discloses an auxiliary arm, an arm frame assembly and a crane, and the auxiliary arm comprises a connecting frame, a short arm group and a long arm group. Wherein the tail part of the connecting frame is used for being connected with the head part of the main arm; the tail part of the short arm group is connected with the head part of the connecting frame, and the short arm group comprises a short arm section and a short arm section luffing mechanism; the tail part of the long arm group is detachably connected with the head part of the connecting frame; the fly jib comprises a single-multiplying-power working mode and a multi-multiplying-power working mode which can be switched mutually; in the single-multiplying-power working mode, the connecting frame and the long arm set are kept connected, and the auxiliary arm is used as a single-multiplying-power auxiliary arm; and in the multi-multiplying-power working mode, the connecting frame and the long a