The invention relates to a connection assembly of a tool rod, relating to a connecting piece for rods, in particular to a connecting element which is suitable for connecting a plurality of rod bodies. The connection assembly comprises an extension-type assistant connecting piece and an extension-type main connecting piece which can be mutually inserted, wherein, the assistant connecting piece is provided with an assistant piece assembly part connected with one end of a first rod body, and an assistant piece insertion part which can be inserted in the main connecting piece is abutted against the assistant piece assembly part; the main connecting piece is provided with a main piece assembly part connected with one end of a second rod body, a main piece insertion part in which the assistant connecting piece can be inserted is abutted against the main piece assembly part; and a locking element is arranged in the mode of synchronously locking the main connecting piece with the assistant connecting piece. The configstructs of the assistant connecting piece, the main connecting piece and the locking element are simpler and much more reasonable, and the assistant connecting piece and the main connecting piece are basically integrated after being mutually inserted, thus, the connection assembly is much more suitable for the fast and convenient insertion and the comfortable for an operator to hold.