Scheelite is the main W- bearing mineral in tungsten deposits. Its unique crystal structure is enriched in trace elements, and it is widely used to implicate mineralization processes and fluid sources. In this research, the mineral assemblage and single- crystal X- ray diffraction analysis of scheelite from oxidized skarn, reduced skarn, wolframite- quartz vein, scheelite- quartz vein, greisen (- skarn) and greisen (- quartz vein) types W deposits related to granite intrusions in Nanling metallogenic belt are presented. The experimental results show that: ① there are some differences in the scheelite crystal structure. The difference in Ca- O bond length data of scheelite in skarn (0.0043 nm) is greater than that of scheelite in quartz vein (0.0035 nm) and greisen (0.0034 nm); ② the difference in Ca- O bond length has little influence on trace elements substitution, but has a great influence on the optimal substitution of REEs. The scheelite in oxidized skarn is developed in multiple stages, and there is a transition from Pr- Nd (prograde skarn stage) to Pr- Sm (retrograde skarn stage) to Nd- Sm (quartz- calcite- fluorite stage) as the optimal substitution of REEs from early to late. The scheelite in greisen (- quartz vein) type deposit presents the REE distribution pattern of the optimal (Nd- Gd) substitution element centered on Sm3+; ③ in scheelite from skarn type and greisen type deposits, REEs enter scheelite lattice mainly through Nb5+ coupling substitution and vacancy substitution mechanism. In scheelite from quartz vein type deposit, REEs enter scheelite lattice mainly through vacancy substitution and Na+ coupling substitution mechanism. In addition, the characteristics of REEs in the parent fluid, the precipitation of associated minerals, the redox environment, the addition of foreign fluids, and the fluid- rock interaction also have a great impact on the substitution of trace elements in scheelite. After all, the scheelite in skarn type deposit is mainly controlled by the precipitation of garnet and other associated minerals. The scheelite in greisen (- skarn) mainly inherits the REE distribution pattern of magmatic fluid. The crystal structure of scheelite in greisen (- quartz vein) has the greatest impact on REEs. However, the scheelite in quartz vein type deposit underwent the multi- phase hydrothermal fluid evolution, showing the changes of bulge- flat- depression MREE types REE distribution pattern.