Wind erosion is one kind of important geomorphology processes and geological disasters, which has significant impacts on dune growth and desertification, and causes damages to architecture on sea coasts. The moisture of sand surface layer greatly affects the threshold wind velocity and sand stability, thus, it is also one of the important influence factors on wind erosion. In this research, the researchers investigated the influence of surface moisture content at 1-mm depth on sand erosion in tropical humid coast of southern China, and established a new predicting model. The modeling results indicated that the threshold friction velocity increased linearly with increasing of ln100 M ( M is gravimetric moisture content) in condition of given sand diameters. Evaluation was given to seven popular models for predicting the threshold friction velocity on moisture sediments, and found that there were significant differences among their predicted results. At a surface sand moisture content of 0.0124 ( M_1.5), the predicted threshold friction velocity predicted by the seven models were 34% to 195% larger than the observed threshold friction velocity on dry sands; at a surface sand moisture content of lower than 0.0062 (0.5 M_1.5), the predicted values by models of Chepil and Saleh well matched the experimental data; but when surface sand moisture content of more than 0.0062 (0.5 M_1.5), the data simulated by the Belly's empirical model were seem same as the experimental data.

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