The utility model relates to the technical field of optical fiber fusion splicing, in particular to a fiber sequence identification heat shrink tube, which comprises an identification tube, an iron core tube, a fixed tube, a tube bundle identification layer and a fiber core identification layer, the iron core tube is fixedly arranged on the inner side of the identification tube, the fixed tube isfixedly arranged on the inner side of the iron core tube, and a left-right through fusion splicing channel is arranged in the middle of the fixed tube; the welding channel comprises a left taper hole,a straight hole and a right taper hole which are sequentially communicated from left to right, the left taper hole is a taper hole with a large left part and a small right part, and the right taper hole is a taper hole with a small left part and a large right part. The optical fiber connector is reasonable and compact in structure and convenient to use, and the fixing tube is prevented from sliding outside the fiber core through the small-aperture straight holes; by arranging the left taper hole and the right taper hole, a to-be-welded fiber core can be conveniently installed in the small-aperture straight hole. The fillets are arranged at the first outer end and the second outer end to prevent the fiber core from being damaged; the colors of the fiber cores to be welded and the colors ofthe tube bundles to which the fiber cores belong are marked through the tube bundle identification layer and the fiber core identification layer.