Abstract: The national high-tech industrial development zone is an important platform for China to develop high-tech industry and actively participate in the international high-tech competition. Research and development (R&D) investment is the important factor influencing the high-tech zone agglomeration development. By constructing a nonlinear threshold regression model, this paper discussed the threshold effect of R&D investment on the agglomeration development of high-tech zones, and conducted in-depth studies on the heterogeneity of threshold effect by grouping regression. The results show that the investment of R&D capital has a decreasing effect on the agglomeration development of high-tech zones in addition to the influence of its own threshold. With the improvement of regional economic development level, the agglomeration development of high-tech zones shows the effect of "inhibition-promotion-inhibition", and the influence of investment in R&D personnel by their own threshold is gradually increasing in promoting the agglomeration development of high-tech zones. With the development of regional economy, the scale of talents is more important than the quality of talents to the development of high-tech zones. In the analysis of the heterogeneity of threshold effect, it is found that threshold effect only occurs in the areas with higher scientific research level, and the impact of R&D investment on the agglomeration of high-tech zones is not obvious in the areas with low scientific research level. Therefore, when formulating policies for the development of high-tech zones, the state should take into account the level of agglomeration development of high-tech zones, local economic development status and the differences in the level of scientific research in local universities, so as to give local governments some room for policy adjustment. According to local conditions, it should guide the R&D activities and agglomeration development of high-tech zones.