Abstract Big data is a leap for human to know and transform the world, which not only deeply influences the development of science and technology, but also deeply affects the modernization process of educational management. Modernization of educational management is one of the targets of educational development, while opportunities and challenges are the two-sided circumstances of China’s educational management in the era of big data. On one hand, big data provides opportunities for promotion of educational management’s diversification, democratization and scientification, normalization of educational management’s conditions, improving the effectiveness of educational management and modernization of educational management. On the other hand, big data’s complexity, uncertainty and low density set up new challenges for modernization of educational management. Lack of data awareness and data talent, risks of information security and invasion of privacy are the complicated dilemma and important conundrum that educational management is facing in the era of big data, which deserves educational management’s subject attention.