Abstract: The wind environment field measurement at the south tower top is executed by the structural health monitoring system located on the Runyang Suspension Bridge. The wind characteristics including average wind speed, wind direction, the turbulence intensity, the gust factors, the turbulence integral length and power spectrum are calculated, based on 300 days field measurement data. The correlation formulations between parameters are proposed. By comparing with the data measured by an anemometer located in the middle of the span, the regulations that average wind speed changes with the height and the correlation coefficient between top and mid-span are obtained. Statistical analysis results reveal that the average wind speed at the top of south tower is low, and the wind direction is stable for the year. The turbulence intensity at the top is stronger when comparing with that in mid-span and the value exceeds the suggestion value of bridge design code seven times. The distribution of the turbulence integral length is almost normal and has correction with the turbulence intensity and average wind speed. Both the longitudinal turbulence power spectrums and transverse turbulence power spectrums can not fit the Kaimal spectrum very well and the parameters of power spectrum density function have close relationship with the average speed. The wind characters of the south tower top are not influenced by that of mid-span because of the long distance of the two positions.