At present, manufacturing enterprises in China and across the world are undergoing a critical period of transformation and upgrading for sustainable development, with various obstacles such as financing difficulties and imperfect production facilities. The emergence of the sharing economy may provide a feasible solution for manufacturing enterprises, but meanwhile, unpredictable risks are bound to arise in the process of Engagement in the Sharing Economy of Manufacturing Enterprises (ESEME), and the assessment for the risk of ESEME is an important issue that requires special attention. Based on the characteristics of ESEME, a risk assessment indicator system is constructed, and a matter-element extension based approach is proposed to assess the risk of ESEME. The comprehensive risk value of ESEME can be calculated, and by means of sensitivity analysis and combinatory analysis, sensitive risk indicators and the risk type of indicators are identified. The innovation is embodied in three aspects: the sharing economy is studied by the matter-element extension method, the minimum deviation weight is adopted, and the risk is identified by sensitivity analysis and combinatory analysis. This assessment method is applied to enterprise E, and good results are obtained. This work is conducive to promoting manufacturing enterprises to engage in the sharing economy, which provides an effective vision for enterprises to implement risk management strategies, and also offers references for the government to formulate relevant policies for ESEME.