Abstract: Based on the interferential theory and diffraction integral theory, the propagation characteristic of Bessel beam generated by an axicon was studied. The applicability and advantages of the theories were discussed as well. The 3-D beam intensity distribution was simulated numerically. The relative parameters were also measured experimentally. The numerical simulation and the experimental results show that, within the maximum diffraction-free distance, the on-axis intensity distribution of the Bessel beam can be described well by the diffractive theory, while the intensity distribution of the Bessel beam approach or beyond the maximum diffraction-free distance can be properly described by the interferential theory. The experimental results are consistent with the theoretical ones.