Abstract: The transverse vibration of microfluid-conveying microtubes embedded in elastic mediums under temperature environments is investigated. The governing equation of the transverse vibration of the tube is established based on the Hamilton's principle and the nonlinear thermoelastic theory, and then solved by using the complex mode method. The natural frequency and the critical flow velocity for buckling instability are obtained and the influences of the surrounding temperature and some major system parameters on the vibration characteristics are discussed. It is shown that the temperature variation, the micro-size effects of both tube and fluid, the outer diameter and the elastic medium rigidity have a significant influence on the natural frequency and the critical flow velocity of fluid-conveying microtubes.