The invention discloses a preparation method of a carbon fiber material product. The preparation method of the carbon fiber material product comprises the following steps of adding an organic adhesive into mixed powder of carbon fiber powder and polyacrylonitrile powder in a light-shielding condition, so as to obtain mixed paste; loading the mixed paste into a 3D (Three-Dimensional) printing forming device, printing layer by layer according to a three-dimensional model of a part by utilizing a controllable ultraviolet light beam and adopting a surface exposure or spot scan way, so as to prepare a carbon fiber product rough blank; carrying out low-temperature degreasing treatment and hot isostatic pressing treatment on the carbon fiber product rough blank, so as to obtain a compact carbon fiber product. A photocuring quick forming principle is utilized for the preparation method of the carbon fiber material product; the shape of the carbon fiber product is not restrained; the preparation method is convenient and quick to operate; further, the product is better in compactness; the vacancy of preparing the carbon fiber product on the market is made up.