Selection?Adaptation theory establishes a coherent and unified theoretical framework of pragmatics, according to which selection is the means, whereas adaptation is the end. By reference to the four angles of pragmatic adaptation proposed by Verschueren and the view of translation as a form of communication characteristic of two inter?language transformations conducted among three participants, the present study attempts to formulate a pragmatic?adaptation?based theoretical framework of translation, and accordingly implement translation quality evaluation of a science article. Under such a translation framework, popular science translation is put forward as selection and adaptation in relation to popular science language, which is characterized with accomplishing popular scientific meaning interpretation and production under the coordination of popular scientific contextual correlates of adaptability, popular scientific structural components of adaptability, dynamics of adaptability regulated by popular scientific cognitive psychology, popular scientific social norms and time, as well as popular science translator’s salience of the adaptation process.