The current velocity of reference period is determined by the local primitive data. A method is introduced to determine the current velocity of reference period through short-range current velocity records for the area that lacks of long-range current velocity records. According to short-range current velocity records of Sutong Bridge the probability distribute mode of the current velocity is established. Presuming the extreme value by way of minority sample，the current velocity of reference period is calculated.Correlation analysis is carried out, the rationality of the calculation is validated and the regression equation is established. The calculated results provide credible technical guide to devise and construct Sutong Bridge and ensure current and wave resistance safety.