Regaring the problems of incomplete scope，updated version and limited application of ship type in the calculation of ship flow force，this paper selects four current mainstream industry specifications of China，the United Kingdom，the United States and OCIMF（Oil Companies International Marine Forum）for analysis and research，and takes the general cargo ship of 20，000 tons as a case for comparative analysis.The results show that there are great differences in the calculation principle，expression form and calculation results of industrial standards in different countries.The American standard has relatively comprehensive and reasonable considerations，while the British standard has certain advantages in ease of use.The distribution of transverse and longitudinal component curves is different.It is suggested that the above calculation method should be reasonably selected according to the applicable ship type，the degree of information of ship data，the mainstream direction angle and the management requirements.The numerical simulation method should be adopted when possible.