Abstract: For the complexity of ship systems,the total ship survivability assessment is required to be dealt with by evaluating separate subsystem or multi-level subsystems respectively,which are to get the complete description through a range of indices of these subsystems.Traditional method using fuzzy analytical hierarchy process(FAHP) in coping with this issue has two shortfalls,on the one hand it likely lead to incorrect calculation, ,while the other it is unable to calculate the weight of interrelated factors between different hierarchies,which limits the scope of the use of FAHP method.A hierarchy model was built by an improved analytical hierarchy process to determine the weight of interrelated factors,and the weight sequence of subsystems were obtained by calculation.An actual assessment demonstrated that the results could reflect the practical conditions of ship systems.Meanwhile,according to the calculated results,the weak links of the total ship survivability can be found,which provides a theoretical basis and method of decision-making for ship damage control operation .