Abstract: Easy and quick manipulation of geometry is the key requirement of an interactive CAD system. One of the most widely used approaches is variational technology. Traditionally, a variational problem can be transformed to the optimization of control points. Unfortunately as the number of basis functions in the set grows, the local support property of B-spline often makes an optimization system poorly conditioned, which results in low efficiency. To solve this problem, a wavelet-based method is presented for the variational modeling of quasi-uniform B-spline curves and surfaces. With the multiresolution property of wavelets basis, the iteration speed can be greatly improved.