Thin　film　mixing　integrated　circuit　has　the　advantages　of　good　function,　miniaturization,　light　weight　and　low　cost.　This　paper　introduced　the　molybdenum　mask　for　the　thin　film　mixing　integrated　circuit　of　micro-heart-sound-stethoscope　by　photoetching.　The　preparation　of　etching　resistant　agent　and　the　photoetching　process　were　described　emphatically.　The　resistor,　capacitor　and　electrode　conducting　wire　were　made　according　to　the　circuit　parameters.