To address the limitations of traditional product and service models and meet consumers’ demands for personalized, intelligent, and seamless experiences, the Smart Product Service Ecosystem (SPSE) has recently garnered increasing attention as a new business model. Ensuring its stable operation is crucial to maintain competitiveness and achieve long-term sustainability. The stability of the SPSE is conceptualized as the outcome of the interconnectedness and co-evolution of multiple factors. Therefore, identifying key factors affecting stability and implementing targeted measures are key to maintaining stable system operation and continuous optimization. In this study, through a comprehensive literature review and analysis of the system’s operating logic, 36 factors affecting the stability of the SPSE are identified based on the dimensions of structure, function, mechanism and benefit. Given the strengths of the ORESTE method and its traditional model’s limitations in fully leveraging decision-making information, this paper proposes a CN-PF-ORESTE model to rank these stability factors. Complex network (CN) captures the correlation among factors and objectively measures the relative importance of factors through the centrality index. Pythagorean fuzzy sets (PF) can deal with the ambiguity of attribute evaluation information. The improved ORESTE model takes into account both the subjective analysis of the expert’s empirical judgment and the objective analysis of the information structure. Finally, the implementation process of the method is illustrated with an example of Smart Home Product Service Ecosystem (SHSE), and the comparative analysis and discussions are conducted to demonstrate its rationality and flexibility.