A composite axicon is presented, which consists of a positive axicon and a negative axicon immersed in index-matching liquid. Analysis results show that it is equivalent to conventional positive axicon, and can be used to generate long-distance nondiffracting Bessel beam.The maximum distance without diffraction depends on not only the refractive index of axicons and index-matching liquid, but also the cut angle of axicons. Therefore, it is a flexible method which not only increases the selection of element material, but also reduces the difficulties of element processing.