The digital transformation of small and medium-sized enterprises (SMEs) has reached a substantive phase of advancement, with significant variations influenced by factors such as management foundations, industry characteristics, and digitalization strategies. Establishing industry-specific models for evaluating digital transformation maturity can provide guidance and assistance for enterprises along the industry chain in their digital transformation practices. This paper focuses on automotive parts enterprises and constructs a Digital Transformation Maturity Assessment (DTMA) model comprising “5 first-level indicators and 23 s-level indicators.” It also develops a five-tier maturity level labeled as “Initial Planning Level,” “Standard Application Level,” “Integrated Control Level,” “Optimization Improvement Level,” and “Digital Transformation Leadership Level.” Utilizing the Group Analytic Hierarchy Process and Fuzzy Comprehensive Evaluation (GAHP-FCE) method, this study evaluates and analyzes the digital transformation maturity of Enterprise L, validating the DTMA model’s applicability and reliability and providing a methodological basis for the assessment of enterprise digital transformation.