Systematic Psychology applies the paradigm and method of systems science and systems philosophy to the study of Psychology and is a significant innovation to Psychology. The book covers a wide breadth of psychological theories and concepts, ranging from psychological thoughts of ancient Greece and Chinese philosophers, to that of various contemporary psychological schools. It establishes the structure of systematic psychology, composed of four types of elements: demand element, will element, cognitive element and emotional element, and concludes that psychological phenomena are formed by the mutual influence and interaction of these four elements. It also creatively proposes the three laws of psychology: the law of will orientation, the law of similarity and the law of butterfly effect, and proves, with mathematical methods, that the core of holistic optimization of mindset lies in the principle of "least action", and the harmonious mindset is the Beauty of Overall Optimization. The book comes up with practical suggestions for the regulation and control of psychological diseases, and the how to achieve the harmony of mentality.