In this paper, we propose to obtain the optical characteristics on material surface by Mueller calculus. In our research, a new metric for Mueller matrices, named R(M) , is defined to describe the polarization and depolarization characteristics on material surface by analyzing the constitute of Mueller matrices. The definition of R(M) is derived from the definition of the depolarization scalar metric for Mueller matrices named Q (M ) which can show the diattenuation and depolarization characteristics. With the advantage of Q (M ) , we assumed and proved the advantage of R(M) against the traditional metrics, the polarizance parameter P(M) and the depolarization index DI (M ) . This comparison can fully illustrate the value of R(M) . It is considered that P(M) and DI (M ) which cannot analyze the optical characteristics commonly to give a comprehensive evaluation. However, composed of P(M) and DI (M ) , R(M) can comprehensively reflect the optical signification which P(M) and DI (M ) represent. R(M) can be used to analyze different optical polarized characteristics on material surface with five bounds as totally depolarizing, partially depolarizing, totally polarizing, partially polarizing, nondepolarizing nonpolarizing. This means that R(M) can enable us to distinguish different materials by their different polarized characteristic on surface. With the definition of R(M) , it can be known that how the optical polarized characteristics work to change the polarized state of incident light on material surface.