In this paper, the robust D stsbility problems are studied by, sine mapping and param-eterization approach. The boundary theorem of robust stability in parameter space is establish-ed, with which we can obtnin some well-known results in robust stability concisely, such as edge theorem. Kharitonov's theorem and diamond theorem for polynomial families. A new approach is presented to judge the D stability of biparameter polynomial family, with which the determination of the largest perturbntion bound of H stable polynomial under given per-turbation patterns (interval model or diamond model) becomes very easy.