The paper takes science & technology personnel, R&D personnel, R&D internal expenditures, R&D investment intensity as the index of scientific & technological input; and takes patent applications, patents authorized amount, technology market contract number and technical contract turnover as the index of science & technology innovation. Firstly, the paper analyzes the overall change trend of the input and innovation ability of science & technology during 1996-2014. Secondly, the paper evaluates the input and innovation ability of science & technology during 1996-2014, based on the principal component analysis. The results show, the overall change trend of the input and innovation ability of science & technology was increasing in Beijing during 1996-2014, and the growth rate of Science & technology innovation capability index was higher than the input index of science & technology. But the input index of science & technology was higher than Science & technology innovation capability index during the period of the ninth five-year-plan to the tenth five-year-plan. Beijing began to focus on promoting the industrialization of scientific & technological achievements, enhancing the dominant position of enterprise innovation, and Science & technology innovation capability index was higher than the input index of science & technology during the period of eleventh five-year-plan to the twelfth five-year-plan.