The risk assessment of key components for smart meters is carried out based on FMECA related theory and risk priority number method. Aiming at the deficiency of FTA and FMEA methods, the application of FMECA method to the quality evaluation of smart meters is proposed in this paper. Then, the risk priority number method is appropriately adjusted based on the actual situation of the smart meter. Finally, the risk assessment and ranking results of key components of the smart meter are conducted in conjunction with the failure of the smart meter in a province in the State Grid in 2018, which provide reference for design, production and quality improvement of smart meter manufactures.