Attitudinal evaluation is one focus of news discourse analysis. Unlike the previous studies which concern how linguistic evaluative resources realize news value, this study focuses on the media-creating process of evaluative meaning. Based on the theory of frame semantics, the study explores the evaluative process which is mutually constructed by contextual frames and value knowledge, and reveals the implicit realization of attitudinal evaluation. It is found that semantic frames are experiential as well as cultural, and their value attributes are key to implied news attitudes; shifted frames can guide readers to recognize news events with specific moral references, and to infer the implicit attitudinal meanings; semantic frames also act as independent signs of attitudinal meaning. The study aims to explore indirect evaluative strategies in news discourse.