Abstract: For the shortcomings of the present IAMs in the aspect of technological progress, this study used an IAM called CIECIA (Wang et al, 2016). In this IAM, a broader concept of low-carbon technology was introduced, and the endogenous of technological progress was realized by R&D driven process technological progress. Based on this model, this study predicted the future global economic growth and carbon emissions, and simulated the impacts of R&D investments on the economies and carbon emissions of countries. The results indicate that in the baseline, developing countries like China and India with higher growth rates will have large carbon emissions in future. China will meet its carbon peak around 2034. The emissions of developed countries with lower growth rates will continue to decline. Improving of R&D investing rates can reduce the carbon emissions effectively, especially in developing countries, and the carbon peaks of developing countries will move ahead largely. While the R&D rates rise up to 7%, most of countries will achieve their INDCs and the global temperature can be controlled under 2℃, and under 16% R&D rates the 1.5℃ target can be achieved in 2100. However, the R&D abilities of countries are limited, and the investing rates cannot be raised sharply in a short time. Thus, the global mitigation target will not be achieved by improving R&D investments only. From the perspective of policy design, R&D improvement promotes economic growths, and thus is quite suited to combine with other reduction measures, compensating for the economic loss by the other measures, and improving the feasibility of mitigation policy portfolio.