Magnetostrictive　materials　have　broad　application　prospects　in　sensing,　control,　energy　conversion,　and　information　conversion.　The　improving　of　the　performances　and　applications　of　such　materials　has　become　a　research　hotspot,　but　defects　will　inevitably　appear　in　the　preparation　and　use　of　materials.　In　this　study,　the　magnetostrictive　structure　model　of　iron　elemental　material　with　no　defect　or　hole　defect　or　crack　defect　is　established　by　the　molecular　dynamics　method.　The　influences　of　different　defects　on　the　magnetostrictive　behavior　of　iron　thin　films　are　analyzed,　and　the　mechanism　of　the　influence　of　defects　on　the　magnetostrictive　behavior　is　depicted　from　the　perspective　of　atomic　magnetic　moment.　The　results　show　that　the　films　with　60　x　2　x　1　defects　in　the　center　are　the　easiest　to　reach　saturation　magnetostriction,　and　the　magnetostriction　is　the　least　after　reaching　saturation,　with　respect　to　the　films　without　defects.　The　films　with　10　x　10　x　1　and　2　x　60　x　1　defects　in　the　center　require　a　larger　magnetic　field　to　approach　to　saturation,　and　the　magnetostriction　of　the　film　with　2　x　60　x　1　defects　in　the　center　reaches　a　maximum　value　after　saturation.　This　is　because　the　defects　will　affect　the　magnetic　moment　of　the　surrounding　atoms　and　make　them　deflect　to　the　direction　parallel　to　the　defects,　thus　affecting　the　magnetostriction　of　the　iron　thin　film.　Among　them,　the　hole　defects　have　less　influence　on　the　magnetostriction,　while　the　crack　defects　have　stronger　influence　on　the　magnetostriction.　The　direction　of　the　crack　also　has　an　effect　on　the　magnetostriction　of　Fe　thin　film.　When　the　crack　is　parallel　to　the　direction　of　magnetization,　the　maximum　magnetostriction　of　the　film　in　the　direction　of　magnetization　from　the　initial　state　to　the　saturation　of　magnetization　will　decrease.　When　the　crack　is　perpendicular　to　the　direction　of　magnetization,　the　maximum　magnetostriction　of　the　film　in　the　direction　of　magnetization　from　the　initial　state　to　the　saturation　of　magnetization　will　increase.　These　results　suggest　that　the　defects　affect　the　magnetostriction　of　the　model　as　a　whole　during　magnetization　by　affecting　the　initial　magnetic　moment　orientation　of　the　surrounding　atoms.