This textbook is compiled in the form of task-driven based on the requirements of computer application basic course in vocational colleges. The book is comprised of 7 chapters systematically introducing the basic knowledge of computer, Window XP, Word2003, Network basis and Internet application, etc. In order to help students consolidate knowledge they have learned and improve practice ability, each chapter is supported with exercises, guiding knowledge introduction through examples, which embodies the essence of integrating teaching, learning and doing. The book can be used as computer application basic course textbook for vocational colleges and adult colleges as well as reference for personnel in computer-related professions.