The survey highlights that most enterprise digital transformation (DT) projects failed to reach the expected outcomes. This is often due to a limited understanding of DT's value and its creation mechanism (VM). The purpose of this article is to compile a list of variables that affect DT's VM and assess the VM factors according to causal links, thereby further understanding of the intricate connections among VM factors. This article adopts a mixed approach called "CS: GT-DEMATEL-ISM" which incorporates the concepts of case study (CS), grounded theory (GT), decision experimentation and evaluation laboratory (DEMATEL), and interpretative structural modeling (ISM). Through GT, 32 concepts related to the DT's VM system were extracted and summarized into 15 VM elements, which further converged into 7 categories: IT, data, process, organization, business, business mode, and values. Using DEMATEL and ISM, DT's VM system model is established, it shows digital technology enables the reconstruction and evolution of data, processes, organizations, and business, thereby establish, or optimize business models, ultimately improve enterprise capabilities and performance. Three main aspects make up research contributions. In terms of methodology, this study suggests that using a mixed approach known as "CS: GT-DEMATEL-ISM" to identify and examine the factors of complex systems. In terms of theoretical and practical contribution, this article is the first to systematically identify DT's values and build the framework of DT's VM system, which fills the gap in DT-related theory and would help enterprise management for DT planning and DT project implementation in DT practice.