China’s economy has transitioned from a high-speed growth phase to a high-quality development phase, and accelerating industrial transformation and improving quality and efficiency have become the top priorities for achieving high-quality economic development. Compared with the strategic requirements and practical exploration of accelerating the construction of a manufacturing power and a digital China, research on digital transformation in China is still relatively lagging behind. The current focus of academic research on digital transformation is still concentrated on its macro- and micro-economic effects. There is a basic consensus on the importance and necessity of enterprise digital transformation, but research on the impact mechanism and policy design of enterprise digital transformation is still relatively weak. This article first extracts the main factors that affect the digital transformation of enterprises based on relevant literature and theories. Then, based on the measurement method of contribution index, the relative importance of the influencing factors of enterprise digital transformation is measured to identify the key factors that determine the digital transformation of Chinese enterprises and their heterogeneity in digital foundation, region, ownership, industry, and executive characteristics. The research results show that the characteristics of enterprises represented by their size, age, and patent stock, as well as the regional environment represented by digital infrastructure and economic development, are the most critical internal and external factors determining the digital transformation of enterprises. The heterogeneity test results show that compared with companies with better digital foundations, the impact of age and marketization on the digital transformation of companies with poorer digital foundations are more critical; compared with enterprises in central areas, digital infrastructure has a more critical impact on the digital transformation of non-central enterprises; compared with non-state-owned enterprises, marketization has a more critical impact on the digital transformation of state-owned enterprises; compared with high-tech enterprises, digital infrastructure has a more critical impact on the digital transformation of non-high-tech enterprises; compared with enterprises with long-sighted executives, the impact of digital infrastructure and marketization on the digital transformation of enterprises with short-sighted executives is more crucial. Compared with existing research, the marginal contributions of this paper are mainly reflected in three aspects: firstly, it expands the relevant research on digital transformation from the perspective of identifying key factors in enterprise digital transformation. Unlike existing research that focuses on exploring the macro and micro economic effects of digital transformation, this article focuses on the “front-end” driving factors of enterprise digital transformation and constructs contribution indicators to identify key influencing factors, which helps to expand and enrich related research on digital transformation. Secondly, research methods have constructed indicators that can measure the relative contribution of each variable. This article draws on the method of Feng Genfu et al. (2021) to improve and redesign the indicators for evaluating the relative importance of variables, applying them to the identification scenarios of key influencing factors in enterprise digital transformation. This helps to scientifically grasp the key influencing factors of enterprise digital transformation and expand the application scenarios of relative contribution indicators. The third aspect is to explore the heterogeneity of key influencing factors on the digital transformation of enterprises in different types of enterprises from several dimensions: digital foundation, location, ownership, industry, and executive characteristics. Based on the research findings, the driving mechanisms and policy designs for the digital transformation of different types of enterprises are proposed, which has important practical significance.