Two optical scintillation methods of measuring the crosswind speed were investigated in the boundary layer. Then, the calculation formulas of wind measurements were proposed. The experiment was carried out at 330 m optical path. Finally the measurements were compared to the results of the sonic anemometer. The results showed two optical scintillation methods were both suitable to determine the windspeed, but the slope technique was more reliable than the peak technique at the time during sunrise and sunset transitions. It was also found that better results can be obtained with the longer time-average. The results demonstrated that a large aperture scintillometer can be used to measure both sensible heat flux and crosswind, so it would be widely applied in evaluation of mass exchange in the atmosphere.