Using infrared spectroscopy and X_ray powder diffraction method, the authors have deterined the structural ordering state and equilibrium temperature of K-feldspar collected from the Jialu gold deposit in Xiaoqinling which belongs to the faulted altered rock type. The K-feldspar is microcline to maximum microcline, whose Al occupancy t1(o)=0.73~1.00, t1(m)=0.26~0, t2(o)=t2(m)=0.03~0, with lattice parametersa0=0.8388~0.8611 nm,b0=1.2837~1.2968 nm,c0=0.7156~0.7248 nm,α=89.906~91.093°,β=115.650~116.230°,γ= 87.500~89.994°. The triclinicityΔ=0.686~1.115, and the equilibrium temperaturet=503.51~578.35℃. Based on the above results, this paper has also dealt with the relationship between the equilibrium temperature of K-feldspar and gold mineralization. The authors hold that Jialu K-feldspar is product of hydrothermal metasomatism, and its heat released in the course of adjusting structural state must have made an impact on the auriferous hydrothermal solution at the early high-temperature stage, thus activating gold complex. This action was unfavorable for gold precipitation, as is more clearly seen with the lowering of the equilibrium temperature and the rising of the triclinicity.