On the basis of the surveyed data of R&D/NPD projects of manufacturing industries in Beijing, the selecton and optimization for preliminary influence factors of R&D/NPD projects of manufacturing industries in Beijing are made, with aid of χ²-test, T-test, and factor analysis respectively. Then, the key factors that influence on different stages of research and development of projects are identified. Furthermore, the results are discussed and analyzed in detail. A more reasonable method for selecting and optimizing preliminary influence factors is presented.