Abstract:This paper presents a detailed method on constructing multi-scaling functions with fractal interpolation functions, then calculates that det H0(z) and det H0(-z) have no common roots, and obtains F0(z) the dual low pass multi-filter of H0(Z) with the perfect reconstruction condition of biorthogonal low pass multi-filters. In order to construct the dual low pass multi-filter of H0(z) with higher approximation order, the two-scale similarity transform is taken for H0(z), then and its dual H0new t(z) is obtained. After applying corre-sponding inverse transform to F0new(z), the dual low pass multi-filter of H0(z) with higher approximation order is achieved.