The invention discloses an internal hexagonal wrench for an electric wrench. The invention aims to provide the internal hexagonal wrench for the electric wrench, that is convenient for the electric wrench to detach and lock internal hexagonal bolts in different models and is capable of effectively relieving the problem of incapability of normally using an external regular hexagonal prism or an internal regular hexagonal prism caused by the incapability of the internal regular hexagonal prism in sliding along a regular hexagonal prism hole under the influence of the deformation of the lateral edge of the internal regular hexagonal prism. The internal hexagonal wrench comprises an external regular hexagonal prism, an internal regular hexagonal prism and a limiting structure; the regular hexagonal prism hole is formed at one end of the external regular hexagonal prism; a wrench spliced hole which is matched with the electric wrench is formed at the other end of the external regular hexagonal prism; the internal regular hexagonal prism is arranged in the regular hexagonal prism hole in a sliding form; in all the inner side walls of the regular hexagonal prism hole: an inner wall deformation reserved accommodating slot is formed at a joint edge between any two adjacent inner side walls and each lateral edge of the internal regular hexagonal prism is located in the corresponding inner wall deformation reserved accommodating slot.