Due to the large amount of greenhouse gas (GHG) emissions and the high dependence on fossil energy, the aviation industry has attracted a lot of attention for emission reduction and sustainable development. Biomass is a green and sustainable renewable resource, and its chemical conversion to produce bio-jet fuel is considered to be an effective way to replace fossil jet fuel and achieve emission reduction. In this study, the cradle-to-grave life cycle analysis is conducted for three bio-jet fuel conversion pathways, including biomass aqueous phase reforming (APR), hydrogenated esters and fatty acids (HEFA), and hydrothermal liquefaction (HTL). Compared with fossil jet fuels, the three bio-jet fuels have a great advantage on global warming potential (GWP), contributing 29.2, 43.6 and 51.2 g CO2-eq/MJ respectively. In general, as a relatively new bio-jet fuel conversion technology, the technology of aqueous phase reforming has minimal environmental impact. If the barriers of raw material availability and economy could be broken down, bio-jet fuel will have great development potential in replacing fossil jet fuel and realizing sustainable development.