| In the past three decades of reform and opening-up, China’s economic and social landscape which was dominated by agriculture and rural areas has changed profoundly with the large-scale industrialization and urbanization. Migrant workers, as a special product of Chinese social change, have gradually become an indispensable part of the city. However, due to the Chinese binary structure of urban and rural and household registration system, this special group has encountered a considerable number of problems, such as various conflicts on life styles and moral values because of social stratification and fission, the restructuring of social order and so on. For this reason, the working and living conditions of migrant workers not only have caught the attention from government and society, but also became hot topic in news media. In recent years, many theoretical and empirical studies on migrant workers have been-done from the perspectives of sociology, journalism and mass communication, but little work has been done within the field of linguistics. This thesis, based on critical discourse analysis, corpus linguistics and cognitive linguistics, focus on the newspaper reports about migrant workers in People’s Daily from1992to2011to make an exploration how "migrant workers" are constructed and represented diachronically in Chinese mainstream press and attempts to reflect the change of mainstream political ideologies and self-cognition of this group, as well as the transformation of government and public’s attitude towards migrant workers during twenty years.On account of a keyword search from online graphic database of People’s Daily from January1,1992to December31,2011, this thesis collects the news reports surrounding the subject of migrant workers spanning twenty years and adopts the methodology combining content analysis and diachronic analysis with case study and general study in order to make a full description on discursive representation of migrant workers in Chinese mainstream news media. By concluding the evolvement of society in the process of image transformation of migrant workers in People’s Daily and analyzing its pros and cons in image-construction, this thesis also hopes to provide some implications for the media producers.The opening section of this thesis first introduces the background and significance of the topic, and then describes the migrant workers’definition, features and history as well as presents research purpose and questions. In the next section, it reviews previous research results on migrant workers in China and the development process and contributions of critical discourse analysis, corpus linguistics and cognitive linguistics in the field of discourse analysis. The third section illustrates the cognitive metaphor theory, frame theory and critical metaphor analysis in usage and the data collection and classification description are also introduced and discussed. Based on the diachronic analysis of sample reports about migrant workers in People’s Daily, the fourth section studies the features of different time periods from the macro and micro levels. The fifth section is the detailed analysis and discussion of the data based on conceptual metaphor theory and Charteris-Black’s critical metaphor approach. It explores the characters, constructing modes and argumentative functions of metaphoric models in different periods and reveals the underlying ideologies of mainstream political media along with social change. The sixth section is devoted to analyze the content and issues of news reports about migrant workers in view of frame theory. It elaborates the gain and loss in the process of migrant workers’ image communication through frame study and its influence on migrant workers’ image constructing. The seventh section offers concluding remarks, summarizing the major research findings and limitation of this study. It also points out that the change of content, genres and topics in news reports not only embody the transition of group identity of migrant workers and their social status in twenty years, but also reflect the transformation of underlying ideologies and evaluation system hidden in news discourse. This thesis hopes to provide new reference and implications for media producers and government. In future research, more theoretical and empirical explorations are expected for making up the flaws in this study. |