Abstract: In this paper, we research the influence factors of R&D input in late-development countries base on the data of 86 late-development countries in the period 2003-2012 using the panel data fixed effects model. The regression result is that the number of researchers and the financial development has a significant positive influence on the R&D input in late-development countries, while manufacturing imports and FDI inflows has a significant negative influence on the R&D input in late-development countries. Further study found that the intellectual property protection level has a significant positive moderating effect for the relationship between financial development, or manufacturing import and R&D input. It is said that the higher level of the intellectual property protection in late-development countries, the financial development can promote more R&D input, and the manufacturing import restrain more R&D input. Future research could be further from the dynamic perspective, not only to investigate the factors that influence the R&D input but analyze its R&D performance.