This　paper　presents　an　analytical　model　for　the　vibration　analysis　of　a　U-shaped　electrothermal　microactuators.　A　U-shaped　electrothermal　microactuator　has　a　unique　geometrical　structure　which　consist　of,　interconnected　multiple　thick　and　thin　beam　segments.　In　this　proposed　model,　both　the　longitudinal　and　lateral　deflections　of　each　beam　segment　are　incorporated.　To　facilitate　the　modelling　process,　a　thick　beam　is　replaced　by　the　thin　beam　segment　using　the　artificial　Young＇s　modulus　and　density　so　that　the　deformation　and　inertia　force　of　the　thin　beam　can　be　used　to　equivalently　describe　that　of　the　thick　beam　segment.　The　relationship　of　the　force　and　deflections　in　both　longitudinal　and　lateral　directions　at　connected　points　between　adjacent　beam　segments　is　formulated　with　continuity　conditions.　The　frequency　equation　is　then　established　subjected　to　two　both　boundary　and　continuity　conditions.　Solving　the　frequency　equation　yields　the　natural　frequencies　of　the　U-shaped　beam　actuator.　The　analytical　results　are　compared　with　the　finite-element　simulation　results　using　ANSYS　software.　A　good　agreement　is　observed　between　analytical　and　simulation　data,　and　hence　the　proposed　vibration　analysis　model　is　verified.　This　model　provides　the　first　insight　study　on　the　vibration　analysis　of　U-shaped　electrothermal　actuators,　which　is　essentially　crucial　to　dynamic　system　modelling,　control,　and　dimension　optimizations.