An algebraic B-spline curve fitting algorithm based on the signed distance field is proposed in this paper.Given a planar point set,the moving least square(MLS)method is adopted to denoise and resample it so that the resulting point set is with low noise and uniform sampling density.Then the reliable signed distance field of the preprocessed point set is constructed by using the Level Set method.Finally,an algebraic B-spline function is adopted to fit the signed distance field by solving a linear equation system.As a result,an algebraic curve is obtained which is the zero level set of the algebraic function.By using the proposed method,not only the high quality curve is obtained,but also geometric information around the curve.Furthermore,the unwanted branches in implicit curve fitting could be avoided.