The invention relates to a method for preparing a brake sheet through adopting calcium carbonate crystal whisker, belonging to the friction material field, wherein the following raw materials of corresponding part by weight are adopted: 5 to 15 portions of adhesive which adopts phenol formaldehyde resin, 20 to 30 portions of reinforcing material which is obtained through mixing steel fiber or ceramic fiber with one or several of aramid fiber, mineral fiber and glass fiber, 1 to 15 portions of grinding agent which comprises one or combination of several of aluminum sesquioxide, ferric oxide, magnesium oxide and friction powder, 5 to 15 portions of lubricant which comprises one or combination of several of graphite, molybdenum disulfide and mica, 5 to 15 portions of stabilizer calcium carbonate crystal whisker, and 30 to 50 portions of filler which comprises one or combination of several of barium sulfate, potassium titanate and magnesium oxide. The brake sheet, which is made through the method, can effectively increase porosity and improve the high-temperature resistance of material, thereby lowering the decomposition rate of organic material at a high temperature; meanwhile, the brake sheet can slow down the gaseous escape speed on a friction surface during fading, thereby reducing fading rate and the change rate of friction coefficient at high speed to less than 10 percent.