Based on a self-established small corpus, Chinese leaders' speeches on the opening ceremony of G20 Summit and Summer Davos Forum are collected. N-gram List and Concordance function in BFSUPowerConc 1.0 beta 25 are used to get high frequency words and make collocation analysis of three selected words "China, development, economy". The findings show that speeches in G20 Summits concern more on cooperation between countries, investment and current challenges, which show our stance and provide guidance for the world economy. However, Summer Davos Forum mainly focuses on Chinese entrepreneurship and innovation, which conveys positive signal of Chinese economy. Although the vocabularies in two corpora differ from each other, they all show China's confidence and determination in promoting the development of world economy.