Based on 6 Sigma theory, this study constructs an evaluation framework and decision support system suitable for the digital transformation of human resource management in small and medium-sized enterprises. Through the questionnaire survey of smes with less than 500 employees, and the data cleaning and analysis combined with 6 Sigma statistical method, the key digital transformation indicators are screened out, and the main challenges in the human resource management module are identified. CART decision tree algorithm was used to model and optimize the transformation process, and the results showed that the prediction accuracy of the model reached 0.6962 when the tree depth was 4. In order to further verify the effectiveness of the evaluation system, word frequency analysis is also carried out in combination with social media data, and the results show that the system has high reliability. This study provides practical decision-making tools for smes in the process of digital transformation, and provides theoretical support for the formulation and optimization of relevant policies