The invention relates to pipe opening inner portion plugging during heat exchanger overhauling, in particular to a heat exchanger overhauling plugging protective device and a use method of the heat exchanger overhauling plugging protective device. The heat exchanger overhauling plugging protective device overcomes the difficult problem of the prior art and structurally comprises a supporting ring1, packing 2, a press ring 3, hexagon nuts 4, square-head bolts 5, a blank flange 6, a compressing flange 8, a soft rubber cushion 9 and a fixing flange 10. The supporting ring 1 and the fixing flange10 are fixed to a heat exchanger pipe opening body in a welded manner. The remaining components all can be mounted or demounted according to needs. When the heat exchanger overhauling plugging protective device is used for plugging, the blank flange 6 and the soft rubber cushion 9 are installed, and the soft rubber cushion 9 is tightly pressed for seal through tightening of the inner bolts; the compressing flange 8 is made to tightly press the pressing ring 3 through tightening of outer bolts, and the packing 2 is tightly pressed for seal. After overhauling is ended, the additionally arrangedtwo circles of packing, the blank flange 6, the soft rubber cushion 9 and the inner bolts are demounted. The heat exchanger overhauling plugging protective device can rapidly and effectively conductplugging protection on a heat exchanger to be overhauled, is easy and rapid to operate and has reference value on the aspect of solving other pipe opening plugging of the same type.