The forefront achievements, which were made by the science and technology in the 20th century, launched great challenges to the previous faiths; the evolution of the concept of science needs new philosophical generalization. Therefore, the process philosophy of Whitehead emerged at the historic moment. From a new visual angle, Whitehead demonstrated the reality of categories or integral substances like individuals, and then specifically provided the way of implementing the reality of categories. The purpose of Whitehead for creating the process philosophy was to overcome the thinking predicament of the traditional substances. Meanwhile, the task and method for reconstructing the foundation of scientific metaphysics were proposed by Whitehead. Whitehead thought that existents were confused with existences in the traditional metaphysics. The root for this phenomenon lied in the cognitive style of the subject-object dichotomy. Therefore, the purpose of overcoming the intellectual subject-object dichotomy of the reality thinking lied in the construction of a process way of thinking. Whitehead also thought that a substance could own a reason for its existence only if it was used as an element of the whole. No matter how necessary the descriptions and analyses on the details of each part are, each part in the whole can only possess certain specificity. However, this specific significance exists for the whole. Universal reality and ultimate reality are always the core issue of philosophy. Nominalism advocates that individuals are real; realism adheres to the reality of categories. The temporary victory of nominalism injected a great power into the development of the modern science. However, the forefront achievements, which were made by the science and technology in the 20th century, launched great challenges to the previous faiths; the evolution of the concept of science needs new philosophical generalization. Therefore, the process philosophy of Whitehead emerged at the historic moment. From a new visual angle, Whitehead demonstrated the reality of categories or integral substances like individuals, and then specifically provided the way of implementing the reality of categories. The purpose of Whitehead for creating the process philosophy was to overcome the thinking predicament of the traditional substances. Meanwhile, the task and method for reconstructing the foundation of scientific metaphysics were proposed by Whitehead. Whitehead thought that existents were confused with existences in the traditional metaphysics. The root for this phenomenon lied in the cognitive style of the subject-object dichotomy. Therefore, the purpose of overcoming the intellectual subject-object dichotomy of the reality thinking lied in the construction of a process way of thinking. Whitehead also thought that a substance could own a reason for its existence only if it was used as an element of the whole.