In an environment of financing constraints, a stable and sufficient cash flow can help reduce the financing uncertainty of high-tech companies and ensure the development of R&D activities. R&D investment-cash flow sensitivity is an important indicator to measure the dependence of R&D investment on financing of technology companies. Some research literature show that the cost of cash flow is lower. When the external financing cost is high, ample cash flow can become an important basis for ensuring the development of scientific and technological enterprises. However, excessive dependence on cash flow will cause high-tech companies to abandon their existing innovative investment projects. Therefore, how to balance and improve R&D investment-cash flow sensitivity is an urgent issue for high-tech companies to consider. From the research perspective of the existing literature, most of the literature focuses on considering the interaction between corporate financing and external capital markets, trying to explore ways to ease financing constraints, reduce cash dependence, and improve the sensitivity of R&D investment-cash flow. However, with the rapid development of China economy, the diversification of business operations and the expansion of business scale, business group organization has become an important form of organization for Chinese enterprises. Research on the improvement of R&D investment-cash flow sensitivity of high-tech enterprises should consider the disturbance of business group organizational factors. Hierarchical theory points out that an internal capital market (ICM) will be formed within the group organization, which uses administrative orders within the group to replace the external capital market allocation and can be used as a supplement and substitute for the external capital market to ease corporate financing constraints. Compared with the external capital market, the internal capital market has the advantages of information symmetry and resource sharing. The introduction of the business groups environment can effectively improve the sensitivity of R&D investment-cash flow. Based on this, this article embeds high-tech companies in the group organization environment and explores the sensitivity of high-tech companies’ R&D investment-cash flow under the joint influence of internal and external capital markets. From the two perspectives of the size and activity of the internal capital market allocation, the discussion focuses on the improvement of the sensitivity of R&D investment-cash flow of technology companies and the mechanism after the introduction of the internal capital market environment. Due to the interrelationship between corporate investment and financing decision-making behaviors, the use of a single equation to test a single indicator may ignore the impact of changes in other indicators. In order to avoid estimation bias, this paper uses the inter-period system equation method to comprehensively analyze the R&D investment of technology companies-cash flow sensitivity. Using the PSM method to construct the experimental group and the control group, to investigate the influence of the group’s organizational attributes on the sensitivity of high-tech companies’ R&D investment-cash flow. The research found in this paper: 1) Group organizational attributes can reduce the sensitivity level of R&D investment-cash flow of technology companies; 2) The allocation scale effect of the internal capital market quantitatively explains the level of R&D investment-cash flow sensitivity of technology companies under the group The reasons for the decrease; 3) The effect of the degree of activity of the internal capital market explains the decrease in the sensitivity level of R&D investment-cash flow from the frequency. Based on this, technology companies can be guided to form a group-like enterprise consortium and use group organizational functions to improve R&D investment-cash flow sensitivity; at the same time, it is necessary to further improve the group’s operating mechanism and control model to improve the operation of the internal capital market mechanism. Effectiveness, to encourage the headquarters to improve the efficiency of capital allocation, and to provide protection for the R&D investment of technology companies under the group.