Although the financing dilemma of small and medium-sized scientific and technological enterprises has attracted extensive attention, while few research paid attention to the dilemma from the perspective of digitization, for this reason, the authors made an theoretical research on influence of digitalization of science and technology finance on financing ability of small and medium-sized enterprise(FASME) by utilizing the comparative method and system analysis tools. Firstly, the authors summarized the realization form of DST, after that, they deduced the mechanism that digitalization of science and technology finance affects the finance ability of small and medium-sized enterprise, at last the authors deployed the challenges faced by science and technology enterprise during the driving process. The results show that, there are significant differences in the influence path and mechanism for different forms of digital realization and among which, the influence of "finance of science and technology+digital technology" is mainly transmitted by "science and technology finance business innovation", while internet science and technology finance innovation for "finance science and technology +digital technology". Through further research, it is found that "innovation of science and technology financial business" promotes the change of information search technology as well as improves the information structure, as a result it optimizes the information environment of credit decision-making and enhances the reverse selection risk avoidance ability. In contrast, the internet science and technology financial innovation is conducive to enhancing the characteristics of science and technology financial system which can reduce the threshold of science and technology finance. Meanwhile, it also can improve the product innovation ability of science and technology financial system and enhance the adaptability of science and technology financial demand. What’s more, the digitalization process enriches the types of science and technology financial models and enhances the robustness of science and technology financial system. In addition, the digitalization development of science and technology finance also leads to the leakage of "adverse selection risk" avoidance ability as well as induces the cognitive confusion of finance agent, what’s worse, it also triggers the supervision gap which restrained the improvement of FASMSE.