The aim of this paper is to identify the factors affecting R&D input of manufacturing enterprises in different local environments of Taiwan. This paper also deals with the relationship between networks and local environments. Local environments with strong or weak innovative energy have different abilities of knowledge spin-off and can be clearly distinguished among regions of Taiwan by 12 indicators considering knowledge facilities, industrial cluster, R&D input and producer services. Networks and local environments are interactive. Technology cooperation networks increase firms' R&D input in a strong innovative environment while it is production cooperation networks having the same effect in a weak innovative environment. Besides, firm attributes are other crucial factors affecting its R&D input. The percentage of employees with certificates and the existence of the R&D department, for example, have positive influence on firms' R&D input.