The invention discloses an iodine flow measuring device. One side of a test absorption cell which needs iodine flow measuring is provided with a light source, the left and right sides of the test absorption cell on the emitting light path of the light source are provided with symmetrical quartz glass testing windows respectively, a focusing lens is arranged between the testing window and the light source, and the outer side of the testing window on the other side of the test absorption cell is provided with a beam splitting slice; the emitted light of the light source which passes through thetest absorption cell is divided into two parts of lights by the beam splitting slice, wherein the beam passing through the beam splitting slice is test light, and the beam reflected by the beam splitting slice is reference light; a test light path and a reference light path on the outer side of the beam splitting slice are provided with the focusing lens, a band-pass interference filter and a silicon probe in order respectively; and the silicon probe is connected with a data acquisition board on the computer through wires, and then the computer carries out data acquisition and data processing. Experimental results show that: the iodine flow measuring device can effectively solve the problem that the measurement is inaccurate, and even cannot be performed because of the pollution of the testing window, and has the advantages of small and exquisite structure and universal applicability.