Abstract: Facial nerve grading system (FNG) plays a crucial role in the diagnosis and treatment of idiopathic facial paralysis, and also serves as a primary tool for prognosis. Subjective grading systems are currently the most widely used methods due to their easy accessibility, popularization and low costs. Objective grading systems, which have obvious advantages in terms of index quantization, repeatability and consistency between evaluators, will become the mainstream in future application and possess development prospect despite their limitation of technology and cost. This article reviewd the clinical application of different types of FNGs in facial nerve grading among different periods, and made a summarization of currently-existing facial nerve grading methods. It may provide a scientific and reasonable reference to the constitution, filter and application of facial nerve grading systems in treating idiopathic facial paralysis.

Key words: facial nerve function, facial paralysis, evaluation, review