Abstract: The level crossing rate and average fading duration can reflect the quality of channel fading envelope along time. A geometry-based stochastic UAV-to-Ground channel model is proposed which supports three-dimensional arbitrary trajectory motion. On this basis, the exact solutions of level crossing rate and average fading duration are analyzed and derived. Meanwhile, an approximate simplified solution for two-dimension scattering scenarios is also obtained. The numerical simulation results under UAV high-speed flight trajectories show that our theoretical results of level crossing rate and average fading time agree well with the simulation ones, and they are also consistent with the actual measurement results under UAV scenarios. Since these results can greatly reduce the computational complexity of statistical properties of UAV channels, it’s helpful for the design of error control coding and block interleaver in UAV communication systems, and significantly improve the analysis of efficiency and simulation of UAV communication systems under complex and dynamic scenarios.