Image fusion based on image transform technologies is always used in multi-focus image fusion. It transforms images into transform domain and fuses the transformed image according to a specific fusion rule. After that, the fused image is achieved by the inverse image transform. The transform based image fusion methods are robust to noise and the fused results are widely accepted. This paper proposes a multi-focus image fusion method based on discrete Tchebichef orthogonal polynomial transform. Discrete orthogonal polynomial transform is firstly introduced to the field of multi-focus image fusion. The proposed method combines the spatial frequency with the discrete orthogonal polynomial transform coefficients of image, and it directly achieves the value of spatial frequency by the discrete orthogonal polynomial transform coefficients of the image and avoids the process of recalculation that transforms the discrete orthogonal polynomial transform coefficients to space domain. The proposed method can reduce the fusing  time in multi-focus image fusion and improves the fusion effect.