Semantics-based notations need to be used for specification of static and dynamic semantics to specify and implement new programming language. If the semantics is practically defined, we easily gain a translator according to the implementation of the semantics. In this paper, we describe the static and dynamic semantics to get a translator easily. We present practical semantics-based Action Equations, an extension and transformation of Attribute Grammar(AGs) suitable for specifying the static and dynamic semantics of a object oriented programming language. Compare with the existing descriptions, Action Equations is superior, modernized, and accurate.