Abstract: In this paper, selecting the data from 1993 to 2017 and taking H shares as the research object, linear regression models, DCC-MVGARCH model and the event research are used to analyze the listing of companies from emerging markets having an impact on the development of the host market and the existing listed companies in the host market. The results of the study are as follows:Firstly, the listing of H shares in Hong Kong has expanded the market size and trading activities of the Hong Kong market, attracting more international capital; Secondly, the listing of H shares in Hong Kong market has improved the returns of H shares and existing Hong Kong stocks. Moreover, the correlation with the Hong Kong market and the global securities market is enhanced; Thirdly, the impact of H-share listings on the valuation of existing shares is also positive. In short, the overall impact of companies listing from emerging markets on the host market and existing listed companies is positive. The spillover effect is greater than the "quality contagion" effect and crowding out effect. Furthermore, it promotes market quality promotion and market development of the host market. The conclusion of this study is helpful to enrich the study of the impact of cross-border listing on the host market, and it is of great significance for China to build an international financial center based on the strategy of opening up the capital market for the "One Belt and One Road" emerging market countries.

Key words: overseas company listing, host market, quality contagion, spillover