A new optical component named detachable combined axicon for generating size adjustable bottle beam is proposed. This new type of optical element is opened a circular hole in the central part of the traditional axicon along the axis. Then a sencond axicon which is maded of common glass materials is embed in the circular hole. Single bottle beams or periodic bottle beams of different size can be generated by the way of replacing the second axicon (or the first axicon) of different base angle in this new optical element. Based on the geometrical optics, the principle of the generation of bottle beam is analysised and the related paramaters of the bottle beam are calculated. According to the Fresnel diffraction integral theory, the intensity distribution of the beam passing through this new optical element is simulated. The results of experiments coincide exactly with the therory discussed above.