The invention provides a carbon-carbon preform and a preparation method thereof. The preparation method of the carbon-carbon preform comprises the following steps of fixedly connecting a first carboncloth layer, a continuous fiber layer and a first mesh blank layer based on a buffer layer so as to obtain a discontinuous layer; fixedly connecting a plurality layers of second carbon cloth layers and a plurality of layers of second mesh blank layers based on the discontinuous layer so as to obtain a continuous layer; fixing a plurality layers of discontinuous layers and a plurality layers of continuous layers on the surface of the buffer layer; and removing the buffer layer so as to obtain the carbon-carbon preform. According to the method, the first carbon cloth layer is in contact with thebuffer layer, one continuous layer is arranged between two adjacent discontinuous layers, and the second carbon cloth layers in the continuous layers are in contact with the first mesh blank layer inthe discontinuous layers. According to the carbon-carbon preform and the preparation method thereof, the plurality of discontinuous layers and continuous layers are alternately arranged on the bufferlayer on a mold so that the carbon-carbon preform can be prepared, joints between carbon fiber cloth and carbon fiber mesh blank are reduced, and the mechanical property of the carbon-carbon preformis improved; and meanwhile, the tension force between the continuous layers can be released, and the mechanical property of the carbon-carbon preform is further improved.