Beginning from the completeness and rationality of the data and standardization of the methods, the designed wind velocity (DWV) for the Shenzhen Bay Bridge is caculated. A 48-year series of yearly maximum 10-minute averaged wind velocity at the 10 m height above surface is obtained through several correcting steps to the original records of yearly maximum wind velocity (MWV) from 1954 to 2001 at Shenzhen Meteorological Station so that meets the requirement of the guidance or standard for the resistance of building structures against wind pressure. Reference wind velocitys (RWV) at different return periods of 200, 120, 100, 60, 50, 30 and 10 years are caculated by adopting the function of Extreme I. It is found that MWV at the automatic meteorological stations near the beach or the bridge is positive correlation with that at Shenzhen Meteorological Station and the averaged value of the former is 10% larger than the later. Further more, the wind velocity over the sea is 4.9% larger than that at the beach according to the standard. So, DWV can be got through enlarging the RWV by a times of 1.1×1.049 (1.154), which is out-extended to every 10-m interval layers under 150 m above the sea surface .