The invention discloses anti-seepage heat insulating rice husk concrete and a preparation method thereof, and the prepared anti-seepage heat insulating rice husk concrete comprises the following raw materials in percentage by mass: 0.6 to 4 percent of rice husk or rice husk powder, 2 to 6 percent of fly ash, 15 to 33 percent of cement, 14 to 27 percent of sand, 26 to 48 percent of stone, 0.15 to 1.2 percent of rice husk coupling agent, 0.11 to 0.29 percent of water reducing agent and the balance of water, and the total mass percentage of the raw materials is 100 percent. The anti-seepage heat insulating rice husk concrete is mainly applied to a concrete lining cannel in a northern irrigation district to prevent frost damage, and tests show the performance of the concrete meets the index requirements of 'Technical Code of Channel Anti-seepage Engineering' on the lining concrete, particularly the heat transfer coefficient of the concrete added with rice husk is only 14 to 20 percent of that of common concrete, and the anti-seepage grade can reach above W4 (the permeability coefficient is less than 0.783*10-8cm/s). Simultaneously, the anti-seepage heat insulating rice husk concrete is applied to non-load-bearing structures or hollow blocks and wall materials in building engineering, is an inexpensive heat insulating material. In addition, the invention opens up a new way for the use of rice husk, and can reduce the harm of combustion to the environment.