This book objectively represents the achievements, status quo, and trends of China Internet development in 2021, systematically summarizes the main experience of China Internet development, and deeply analyzes the strategic planning, policies and measures, and development achievements, level, and trends in China in terms of eight aspects, i.e., information infrastructure, information technology, digital economy, e-government, cyber content, cybersecurity, cyberlaws, international cyberspace governance, and exchanges and cooperation. This book further optimizes the index system of China Internet development and comprehensively evaluates the work of cybersecurity and informatization in 31 provinces (autonomous regions, municipalities directly under the Central Government, excluding Hong Kong, Macao, and Taiwan) across the country from six dimensions, in order to mirror Internet development level in China and various regions in a comprehensive, accurate, and objective way. This book collects the latest research results in China Internet development and selects the latest cases and reliable data. With diverse subjects and detailed discussion, this book possesses great significance for these engaged in Internet field in governmental departments, Internet enterprises, scientific research institutions, and universities, who hope to fully understand China Internet development.