Abstract: With the continuous development of 6G communication technologies, higher requirements are imposed on the transmission rate and link stability of maritime unmanned aerial vehicle (UAV)-unmanned surface vehicle (USV) communications. To fully characterize the unique properties of maritime UAV-USV channels, this paper investigates and characterizes the key statistical characteristics of channel models in the sub-6 GHz and millimeter-wave frequency bands. The investigated characteristics include channel correlation, delay spread, stationary interval and average received power. The influence laws of sea surface roughness, evaporation duct, rainfall weather and motion states of transceivers on channel characteristics are also deeply analyzed. The results show that the increase of environmental complexity reduces channel correlation and disperses the arrival time of clusters. The temporal autocorrelation of channels decays to a low level within 0.01 s, and the spatial cross-correlation drops to a specific value at 0.02 m and then fluctuates obviously. The stationary interval is significantly affected by the environment and is mostly concentrated within 0.1 s. The simulated root mean square delay spread is in good agreement with measured data, which verifies the accuracy of the proposed model. This study effectively improves the adaptability of traditional maritime channel models in high-frequency bands and expands their application scenarios in complex marine environments. It can provide statistical support for the deployment and optimization of future 6G maritime communication networks.