In this paper, a kind of composite microtube, which is made from superfine silk powder and polyurethane, reinforced by polyster and spandex tubular fabrics, was examined. The cross-section of composite microtubes were microporous, and micropores were uniform distributed, the inner surface was relatively smooth. The results showed that the wall thickness of composite microtubes increased, which led to the strength,the breaking work and the initial modulus incresead; that the spandex content increased brought about the initial modulus and the breaking work decreased, but the breaking extension and the breaking load were firstly increased and then decreased; and all the mechanical properties decreased as the SFSP content increased.