Abstract: We focus on the policies of the development and construction of Liaoning free trade zone in different periods,and carry out a low-dimensional theme collection of the phased policy texts of free trade zone construction through LDA big data model,which can identify the hidden theme information,theme intensity and structural characteristics of large-scale documents.On this basis,compared with the central government's requirements for the development of Liaoning free trade zone,we can accurately explore the focus and development gap of local policy implementation,and then identify the deficiencies in the construction and development of free trade zone.It is found that in terms of theme intensity,the similarity between themes is low and the intensity gap is not obvious;in the theme field,policy promulgation focuses more on administrative examination and approval,regulatory innovation,project construction and other areas.However,it is weak in the fields of investment,trade,foreign exchange management,financial services,scientific and technological innovation,talent policy and so on.In the theme structure,the policy themes of administrative examination and approval and performance appraisal aim at the reform of administrative system and mechanism,while the themes of regulatory innovation,government information disclosure and electronic information service reflect the policy supply focus of "service-oriented government".Based on this,it is necessary to strengthen the policy supply in the areas of finance and trade,the construction of the business environment under the rule of law,the introduction oftalents,and enterprise support.

Key words: LDA thematic model, Liaoning free trade zone, policy texts, cluster analysis