The invention relates to a vortex burner recirculation area length measuring device and method. The device comprises a first wind direction detection element, a second wind direction detection element, a distance measuring element and a calculating element. The first wind direction detection element and the second wind direction detection element are arranged on a nozzle axis and can synchronously move along the axis. The distance between the first wind direction detection element and the second wind direction detection element is preset length. In the process of synchronous movement of the first wind direction detection element and the second wind direction detection element to the direction of the hearth of a vortex burner from the position of a nozzle, the distance measuring element measures distance of synchronous movement when different wind directions are detected, and the calculating unit calculates length of a vortex burner recirculation area according to the movement distance and the preset length. Length of the recirculation area can be conveniently and accurately calculated by detecting change of wind direction in the recirculation area so as to determine the corresponding relationship of a vortex blade angle and length of the recirculation area.