The design code of concrete structures was revised in 1986 by the Japan Society of Civil Engineers. In this code, Standard values of load factors and material factors are prescribed. On the application of the code to port and offshore structures, safety factors such as load factors must be examined taking into account the characteristics of loads and structures.
　In this report, the mean and the coefficient of variation of seismic load in lifetime of structures was calculated based on the data of acceleration in port and harbour area. Also, load factors of seismic loads were calculated for each point. Furthermore, the average of load factor was calculated for each five zone which is used in the design for liquefaction prevention on coastal area.