Small-caliber pipeline flaring tool and using method

The invention provides a small-caliber pipeline flaring tool which comprises a flaring end and a flaring end, the flaring end comprises a base, a conical head and a puller bolt, the puller bolt is movably arranged on one side of the base and pushes the conical head, and the conical head is movably connected into the base in a sleeved mode; the clamping end comprises a shell in threaded connection with the base, the shell and the base form a movable space and a clamping cavity which are communicated in the shell, and a wedge block is arranged in the clamping cavity. The structure is simplified into the detachable clamping end and the flaring end, the movable space and the clamping groove formed between the shell and the clamping base are used for providing proper buffer space for clamping and flaring of a pipeline, the flaring base and the puller bolt are used for reducing the pushing space and path of the conical head, and the coaxiality in the pushing process is guaranteed; according to the device, the opera