In　order　to　reduce　the　vibration　of　the　double-sided　meshing　nutation　drive　with　double　circular　arc　spiral　bevel　gears,　the　dynamic　modal　of　the　nutation　system　is　analyzed.　The　bending-torsional-axial　coupling　nonlinear　dynamic　model　of　the　double-sided　meshing　nutation　drive　system　with　time-varying　meshing　stiffness,　meshing　damping,　transmission　error　and　tooth　backlash　is　established,　and　the　equation　of　motion　of　the　system　is　derived.　The　natural　frequencies　and　corresponding　modal　modes　of　the　nutation　system　are　calculated,　and　the　effects　of　the　average　meshing　stiffness　of　gears　and　the　bearing　support　stiffness　of　nutation　gears　on　the　modal　of　the　system　are　analyzed.　The　modal　analysis　of　double　circular　arc　spiral　bevel　gears　is　carried　out,　and　the　ten　order　natural　frequencies　and　their　corresponding　modes　are　obtained.　The　results　show　that　the　nutation　drive　system　and　the　double　circular　arc　spiral　bevel　gears　do　not　resonate　during　transmission.