Nondiffracting Bessel beam is less disturbanced when propagating in the atmosphere. It′s very suitable for alignment and measurement on large scale. To overcome the limited nondiffracting distance generated by the traditional axicon, two kinds of combined axicons based on the transmission properties of conventional axicons, are proposed for generating long-distance nondiffracting Bessel beam. Transmission properties of combined axicons are analyzed and simulated by optical ray tracing and diffraction theory. The results show that two kinds of combined axicons are equivalent to conventional positive axicon on transmission properties, but both of them can generate high quality and long-distance nondiffracting Bessel beam. Meanwhile, they also reduce the difficulties of element processing.