Abstract: The low-level jet (LLJ) is closely concerned with severe rainfall events, air pollution, wind energy utilization, aviation safety, sandstorms, forest fire, and other weather and climate phenomena. Therefore, it has attracted considerable attention since its discovery. Scientists have carried out many studies on LLJs and made significant achievements during the past five or six decades. This article summarizes and assesses the current knowledge on this subject, and focuses in particular on three aspects: (1) LLJ definition, classification, distribution, and structure; (2) LLJ formation and evolutionary mechanisms; and (3) relationships between LLJ and precipitation, as well as other interdisciplinary fields. After comparing the status of LLJ researches in China with those abroad, we then discuss the shortcomings of LLJ research in China, which might cover the coarse definitions of the LLJ, lack of observations and inadequate quality control, few thorough explorations of LLJ characteristics and formation mechanisms, and limited studies in the light of interdisciplinary fields. The future prospects for several LLJ research avenues are also speculated.