The threshold power of 1.2 μm laser generated from the Ho3+: LLF crystal was discussed. Two typical quasi-three-level theoretical models were used to analyze the effectiveness of 1194 nm laser's threshold power in the in-band pumping source of 1.15 μm fiber laser with different parameters, such as the absorption coefficient of laser medium, the laser beam radius, the crystal length and reflectivity of the output mirror. It was found that the re-absorption loss was the most important factor leading to the different results for the two models, and the second model was close to the practice because of the narrow bandwidth pumping beam(<6 nm). The results provided reliable data of Ho3+-doped 1.2 μm solid-state laser systems for the design and experimental research in further.