In recent years, the research work of smart grid has been carried out in all countries in the world. Smart grid has the basic characteristics of information technology, digitization, automation and interaction, its ultimate goal is to become the construction of power system covering the whole production process, including power generation, transmission, substation, distribution, power dispatching and other aspects. It is a security, self-healing, green, reliable system. To achieve safe and reliable operation of smart grid, we must rely on powerful data collection, analysis and processing technology. With the development of Internet technology, especially in recent years, cloud computing, Internet of things and modern communication technology have been rapidly developing to show the arrival of the era of big data. The development of large data technology has injected great vitality into the smart grid, and the convergence of the two is also the trend of the times. This paper introduces the basic concept and characteristics of big data and smart grid, and the key technology of large data acquisition and data fusion technology, protocol technology, data display technology three aspects of big data technology in smart grid application are discussed, and an overview of big data grid applications can face in intellectual challenges.