The emergence of mega-city regions has been the highlight of China in its 30 years of reform and opening-up and urbanization process.To probe into the urban development model of PRD mega-city region，the author reviews the formation history and analyzes the development process of the region with the use of a series of related theoretical concepts and a comparison of three mega-city regions in China.The detailed analysis of the dynamic mechanisms and trends of the regional innovation sums up the experience of success and helps to provide guidance and direction of the region in the new round of development cycle.