The active opening of eustachian tube is the only mechanism of ventilation of meddle ear. Obstruction of nasopharygeal air way, mechanical occlusion of tubal orifice and inflammatory reaction of the nasopharyngeal mucosa couse dysfunction of the eustachian tube. Authors studied the relationship between each etiology and the degree of ventilating dysfunction of middle ear by comparison a group of anterior nasal packing after intranasal surgery with one of tonsillectomy. Results were as followings ; 1) The changes of middle ear pressure in operation day of ipsilateral anterior nasal packing group was -48mmH₂O, in 1st postoperative day(POD) 28.4mmH₂O, and normalized one day after packing removal. 2) In the group of bilateral anterior nasal packing, in op. day -41.2mmH₂O, at 1st POD -55.7mmH₂O, and normalized 2 days after packing removal. 3) In tonsillectomy group, the pressure change in op. day was -40.7mmH₂O, in 1st POD -44.2mmH₂O in 2nd POD -22mmH₂O and normalized in 4th POD.