The invention discloses a preparation method of a low-density carbon fiber composite acoustic panel for KTV. A needled staple fiber body is taken as a preform framework, and hardness treatment is performed with resin impregnation, curing and charring processes. The method comprises the following steps: 1, adopting a needled carbon fiber body as a preform material; 2, preparing a resin impregnationsolution; 3, performing resin impregnation; 4, performing curing treatment; 5, performing charring treatment; 6, preparing the low-density carbon fiber composite acoustic panel for KTV after machining. The low-density porous carbon/carbon acoustic panel adopting carbon fiber as the framework and a resin carbon matrix as a reinforcement body has the advantages of being waterproof, fireproof, aging-resistant, good in impact resistance, pollution-free to the environment after being wasted due to low-energy-consumption and environment-friendly materials, good in sound absorption effect in use andthe like.