Based on field measurement of the wind field and wind pressures of the tower top of Dongting Lake Bridge,wind pressures, wind speed and direction time series were obtained. And the characteristics of wind field,the distribution of wind pressures, the mean wind pressure coefficients and fluctuating wind pressure coefficients of the tower top were analysed.The results show that the change of mean wind pressure coefficients of each point of windward side tends to be identical,that the fluctuating wind pressure coefficients of windward is relatively higher and the leeward one is relatively lower,that there is less difference in the fluctuating wind pressure coefficients on the same side and that the fluctuating wind pressure coefficients is two to three times as large as the turbulence.