In　this　paper,　the　condensation　oscillation　phenomenon　during　steam-air　jet　process　with　air　mass　fraction　of　1%∼5%　in　the　condensation　oscillation　region　was　studied　experimentally.　It　was　found　that　steam　bubble　was　wrapped　by　air　all　the　time　during　the　condensation　process.　With　air　mass　fraction　increasing,　the　wrapper　layer　was　thicker　and　the　movement　period　of　steam　bubble　increased.　Besides,　with　air　mass　fraction　increasing,　the　peak　of　pressure　oscillation　intensity　decreased　and　the　peak　position　moved　downstream　along　the　axial　direction.　When　air　mass　fraction　was　higher　than　2%,　the　oscillation　intensity　decreased　obviously.　Moreover,　there　appeared　two　oscillation　frequencies.　Two　frequencies　both　decreased　as　air　mass　fraction　increased.　When　air　mass　fraction　was　lower　than　2%,　two　oscillation　frequencies　changed　severely.　©　2019,　Science　Press.　All　right　reserved.