Abstract: In identification of nonlinear system, the system inputs usually are non-uniformly distributed. The approach using orthogonal wavelet network (OWN)to tackle this problem is complex.This paper transfers non-uniformly distributed data into uniformly-distributed data using grouping median method such that the design and application of orthogonal wavelet network can be completed on the grid structure. In addition, a weighted band-wise OWN is proposed to be combined with system design. The advantages of this method are noise-free, computationally efficient, easy to understand. Finally, a nonlinear dynamic system is identified, the results of simulation show that it is feasible and effective.