Smart grid is one of the most important application situations for big data. The application of cloud computing technology as the core of large data technology has become an inevitable choice for the development of current and future power enterprises. Based on the data acquisition architecture of smart grid, this paper enumerates the application cases of big data technology in the process of smart grid construction, such as transmission line disaster prevention and early warning, equipment operation status assessment, active service of key customers, cracking down on breach of contract stealing and visualization display, etc. This paper has summarized the key technologies of big data and research ideas and discussed the problem of big data technology in smart grid. At the end of the paper, a rational prospect for the development of big data technology in smart grid has been explored.