The present disclosure relates to the field of anode materials, and provides an anode material, a method for preparing the anode material, and a secondary battery. The anode material has a core-shell structure. The core includes a silicon-based active material. The shell includes a connecting layer, a buffer layer and a protective layer. The connecting layer is coated on the surface of the silicon-based active material. The buffer layer is filled between the connecting layer and the protective layer. The connecting layer is connected to the buffer layer via a covalent bond. The anode material of the present disclosure has low cost and can be produced on a large scale, and the method for preparing the anode material can reduce the volumetric expansion of the anode material and improve the structural stability and cycle stability of the anode material.