Using the theory of new economic geography, this paper constructs a theoretical model of the agglomeration of high-end service industry and the flow of R&D factors affecting the competitiveness of high-end service industry. Theoretical analysis shows that the competitiveness of high-end service industry is positively correlated with the agglomeration degree of high-end service industry, the flow of R&D factors, the number of labor force and the share of industrial product expenditures, and negatively correlated with the elasticity of substitution between products. Then, using the data of 31 provinces in mainland China from 2003 to 2018, spatial exploratory analysis found that there was an obvious spatial positive autocorrelation in the competitiveness of high-end service industry among Chinese provinces. The test results of spatial panel econometric model also well support the conclusion of the theoretical model. It shows that the improvement of high-end service industry agglomeration, R&D personnel flow and R&D capital flow positively promote the competitiveness of high-end service industry, but the total effect of the three is mainly determined by the direct spillover effect. The conclusion of this paper provides policy enlightenment for China to further promote the agglomeration of high-end service industry, coordinate the flow of interregional R&D factors, and then enhance the competitiveness of China''s high-end service industry.