Abstract: In response to no mature analytical model for the jet from flowing artesian wells, including well discharge and jet height, systematic research was conducted. First, based on the principles of well flow, jet flow, and water flow continuity, a steady flow analytical model for jet from a flowing artesian well was established, and a closed form solution was derived, upon which its practical implications were discussed. Second, to characterize jet status, the concept of jet potential of a flowing artesian well was proposed, encompassing both apparent jet potential and substantial jet potential. For the quantitative analysis of substantial jet potential, the expression of jet power was derived. Third, through systematic theoretical deduction, an in-depth analysis was conducted on the impact of three fundamental hydraulic factors (flowing hydraulic head, specific well discharge, and wellhead area) on the jet potential of a flowing artesian well. Finally, the theoretical results are validated through application to a practical case. The results indicate that: (1) Jet is entirely determined by three fundamental hydraulic factors. (2) The apparent jet potential provides an intuitive measure of jet status and serves as an external functional indicator of flowing artesian well, while the substantial jet potential can more accurately characterize the status of the well from a mechanistic perspective. (3) The three fundamental hydraulic factors are sufficient and necessary conditions for the jet. Among them, the flowing hydraulic head is the source of energy and supply, whose impact on jet is positively correlated and unbounded. The specific well discharge reflects the runoff channel and has a positive correlation and bounded impact on the jet potential. The area of the wellhead represents the drainage capacity of a flowing artesian well, and is also the “main switch” and “regulator” for jet, whose impact on jet potential is “bidirectional”; theoretically, there exists a “maximum jet potential wellhead area”. (4) The prectical case studies have demanstrated that both forward and invevse analysis can be conducted by this research with high precision (the relative error of well flow discharge is within 1%,the absolute error of jet height is only 0.03 m, and the relative error of specific well discharge is within 1%). At the same time, it also explains from the perspective of caculation and analysis that three basic hydraulic factors have a significant impact on the formation of the jet potential characteristics and working status of the flowing artesian well. Systematic theoretical derivation and case application demonstrate that this study not only reveals the hydraulic essence of jet in theory but also provides important guidance for the design and operation of flowing artesian wells, as well as for the inversion of hydrogeological parameters by jet observations.