Abstract: Low-level jets (LLJ), as a common specific wind condition in the marine atmospheric boundary layer, significantly alter the inflow wind speed distribution of wind turbines, consequently inducing variations in wind power generation characteristics. Investigating the impact of LLJ on wind turbine power generation is one of the critical foundational issues in offshore wind energy research. In this paper, the mainstream 15 MW floating offshore wind turbine (FOWT) is taken as the research object. Based on actual measured data from wind farms and combined with the fluid mechanics theory, the LLJ wind speed field model is introduced. Based on validating the model's efficiency in accurately depicting the characteristic parameters associated with LLJ, a systematic study is conducted on the impact of LLJ parameters on wind turbine power generation, with jet height, jet intensity, and LLJ intensity as control variables. The results demonstrate that neglecting LLJ inflow characteristics may significantly amplify wind power prediction errors, with power reductions reaching a magnitude of 50% compared with normal wind conditions at equivalent hub-height wind speeds. Notably, assessing whether LLJ occurrence adversely affects power generation cannot rely solely on single parameters such as jet height, jet intensity, or LLJ strength. Instead, a comprehensive consideration of these three LLJ characteristic parameters is necessary. Furthermore, blade torsional deformation and its synergistic coupling effects significantly influence the power calculation accuracy, which must be rigorously incorporated into numerical simulations for FOWT.