Alineardirectedforestisadirectedgraphinwhicheverycomponentisadirectedpath.Thelineararboricityla（D）ofadigraphDistheminimumnumberoflineardirectedforestsinDwhoseunioncoversallarcsofD.Foreveryd-regulardigraphD,NakayamaandPerocheconjecturethatla（D）=d＋1.Inthispaper,weconsiderthelineararboricityforcompletesymmetricdigraphs,regulardigraphswithhighdirectedgirthandrandomregulardigraphsandweimprovesomewell-knownresults.
