In　order　to　study　the　effects　of　ultrasonic　parameters　on　the　microstructure　and　mechanical　properties　of　noncontact　ultrasonic　assisted　laser　deposition,　Fe-based　powder　was　deposited　on　42CrMoA　steels　with　different　ultrasonic　amplitudes　(UA)　and　excitation　distances　(d).　The　results　show　that　the　ultrasonic-assisted　laser　metal　deposition　(LMD)　of　Fe-based　powder　increases　depth　and　width　of　the　deposition　layers.　Due　to　the　cavitation　effect　of　ultrasonic,　it　effectively　refines　the　grains　and　promotes　the　columnar　to　equiaxed　transition　(CET)　of　grains　at　the　interface.　When　d　=　50　mm,　the　grain　size　greater　than　8　mu　m　accounts　for　only　3.1　%,　but　the　ultrasonic　vibrations　haven＇t　changed　the　phase　type　of　the　structures.　With　ultrasonic-assisted,　the　cracks　generated　in　the　deposition　layer　can　be　effectively　inhibited　and　the　mechanical　properties　can　be　improved.　When　d　=　80　mm　and　UA　=　30　mu　m,　the　average　microhardness　of　the　deposition　layer　reaches　772.9　HV,　which　is　95.8　HV　higher　than　that　without　ultrasonic-assisted　deposition.　When　UA　=　40　mu　m,　the　tensile　strength　is　1237.9　MPa,　which　is　increased　by　26.8　%　compared　to　without　ultrasonic-assisted　deposition.　Compared　to　without　ultrasonic-assisted,　the　friction　coefficient　of　deposition　layers　is　significantly　decreased　by　25.5　%　with　the　application　of　UA　=　30　mu　m.