Under the condition of fully considering the current status quo of the upgrading and transformation of intelligent manufacturing of small and medium-sized enterprises, intelligent manufacturing is divided into five development stages of lean, automation, digitalization, intelligence and interconnection, so as to build an index system and combine PSO-ELM algorithm to build an evaluation model for the maturity of intelligent manufacturing capabilities of small and medium-sized enterprises. At the same time, 137 valid data of small and medium-sized enterprises are obtained in the form of enterprise surveys and it is proved that this model is reasonable as the development path of intelligent manufacturing of small and medium-sized enterprises in accordance with the five stages of lean, automation, digitalization, intelligence and interconnection, and is more suitable for small and medium-sized enterprises than the existing standard model, and from the training test results of PSO-ELM algorithm, the algorithm is feasible and accurate for the evaluation of the maturity model of intelligent manufacturing capabilities of small and medium-sized enterprises.