In order to explore a controllable, stable and efficient method for preparing carbon nanohorns, Nd∶YAG laser with high power and short pulse was used to irradiate natural flake graphite particles suspended in liquid medium. The experimental products were characterized by high resolution transmission electron microscopy and laser Raman spectroscopy. The experimental results were analyzed theoretically and experimentally. The results show that, when laser energy is 150mJ, 300mJ, 450mJ and 600mJ, the corresponding products are carbon nanohorns of seed type, bud type, dahlia type and petal-dahlia type respectively. The particle sizes of the four kinds of carbon nanohorns are all distributed in the range of 10nm to 80nm with average sizes of 29nm, 33nm, 36nm and 38nm, respectively. This study is helpful to prepare different forms of carbon nanohorn materials.