Given a measurable function λ with λ ∞ < 1, the approximating solutions of Beltrami equation for λ are directly constructed by using the techniques of SG circle pattern and conformal welding. It is proved that the sequence of approximating solutions converges uniformly on to compact subsets to a quasiconformal mapping with complex dilation λ. This provides a new approach of constructing discrete quasiconformal mappings.