Abstract: Quantum physics is the cornerstone of contemporary science, and has led to a revolution in high-tech development. Its combination with information science has resulted in the interdisciplinary field of quantum information. It provides a new train of thought for overcoming the limits of computer chip size. Since 1987, our investigations on quantum open system theory, quantum ecoherence, and the fundamental problems of quantum physics have kept pace with the rapid development of quantum information science in the last decade. Starting with Huan-Wu Peng's important research on open quantum systems (the quantum damped harmonic oscillator) at the end of the 1970s, we will review the basic concepts and scientific importance of this field. At the same time, we will give a brief description of our series of studies on the theory of quantum open systems and its applications in quantum information.