Prof. Dai was elected as a member of the Chinese Academy of Sciences in October, 1995 and a member of International Academy of Sciences for Europe and Asia on December, 2012. Prof. Dai has been engaged in the geological and geochemical research work of natural gas in the past 40 years. He has established the coal-derived gas theory in China which shed lights on a brand new exploration field for natural gas in the country; and made great contributions to establish the first batch of abiogenic alkane gas fields and abiogenic CO2 gas fields and their geochemical characteristics; . He has made a distinguished contribution to the identification of natural gases with different genetic types; made significant contribution to the formation condition, quantitative and semi-quantitative controlling factors, and the prediction of favorable areas prediction of giant gas fields in China; . Professor Dai has made initiative contributions to the geochemical research on unconventional natural gas (coalbed methane, tight sand gas and shale gas) in China. In a word, systematic and creative contributions have been made by Prof. Dai which that improves fostered the rapid development of the Chinese natural gas industry.