Itiswellknownthatthesinglelinearraysonarcan'tidentifywhetherthetargetcomesfromleftorright.Multi-linearrayprovidesthepossibilitytosolvetheleft-rightambiguityproblem.Theperformanceofleft-rightresolutionfortwin-linearrayisdescribedinthispaper.Itisshownthatthesuppressionratio,whichisdefinedastheratiooftheresponseinthesteeringdirectiontooppositesymmetricaldirection,canbeconsideredasanindexforevaluatingtheabilityofsolvingleft-rightambiguity.Thecharacteristicsofsuppressionratioisdiscussed.Thetheoreticalexpressionforsuppressionratioandsomenumericalresultsareillustrated.Theresultoftheoreticalanalysiscanbeusedindesignoftwin-linearraysonar.