China is just starting the industrial development of shale gas due to its great potential in shale gas resources although do- mestic researches on the comprehensive assessment, production mechanisms and production technologies of shale gas remain imma- ture. Based on the authors~ previous investigation and extensive literature search, this paper gives an overview on advances in the re- search and development of shale gas both at home and abroad, which discusses the following aspects： （1） the comprehensive assess- ment of shale-gas resources is the first step in shale-gas exploration and development and the key parameters and factors that deter- mine the potential of shale gas are analysed; （2） production mechanisms of shale gas are fundamental to reservoir modeling, numeri- cal simulation and hydro-fracturing design, and therefore, the complex production mechanisms and flow models are summarized. （3） some key technologies applied to shale-gas development, such as horizontal well and hydraulic fracturing, and the intrinsic correlation between reservoir characteristics and technologies chosen are discussed, which provide a reference basis for production optimization; （4） a review of the development history, characteristics and future development expectation of shale-gas resources in China.