CausesofLexicalChangeofEnglishWordsabstract：asiswellknown,englishisaninternationallanguage.forthechangingoftime,thedevelopmentofscienceandtechnologyandtheevolutionofmind,thelanguagewhichisthereflectionofrealityshouldkeeppacewiththedevelopmentofthesocietyaccordingly.therefore,facingsomanyandcomplicatedenglishwords,alanguagelearnercandonothingbuttograspthereasonsofitsdevelopmentinordertolearnenglishwordsbetter.thispaperseekstofocusonthetwomainreasonsofthelexicalchangeofenglishwords.keywords:scienceandtechnology;politicalchange;economicalchange;socialchangecausesoflexicalchangeofenglishwordsi.introductionnowadays,wecaneasilyfindthatlexicalchangesinenglisharekeepingstrikingoureyes.somewordshavecomeintoappearanceinallaspectsofourlifewhilesomewordshavedisappearedastheylostthefavorofpeople.facingsomanyenglishnewwords,howcantheenglishlearnerslearnthemefficiently?theansweristhattheyshouldpaymoreattentiontothechangesinlexicon.itisveryhelpfulforenglishlearnerstolearnenglishwordswhentheyknowwhywordschange.therearemanyreasonsforthelexicalchange.thepaperwilldiscusstwomainreasons.ⅱ.thedevelopmentofscienceandtechnology“asscienceandtechnologydevelop,peopleusenewwordstoexpressnewconcepts,newtechniquesaswellasnewinventions”(戴炜栋，何兆熊105).gozzistatesthatbetween1961-1986forty-fivepercentofthosenewwordsarefromthescientificandtechnologicalfield(13).hisstudyalsoappliestothesituationtoday.herearesomeexamplesinthreedifferentdomains:spacetravel,computerandinternetandecology.1.spacetravelwiththedevelopmentofspacetravel,somewordsandphraseshavebeencoinedtorecordtheseachievementsofhumancivilization,suchasiss(国际空间站),deepspace(远空间),blackhole(黑洞),spacesuit(宇宙服),spacestation(太空战),moonscape(月球表面),hatch(舱门)andquasar(类星体).2.ecologyasmoreandmorepeoplebecomeconcernedwiththepreservationoftheenvironmentandnaturalresources,quitealotofwordshaveappearedinourlife.thefollowingpartisanexample.我们可以看到ecoacrivist(生态学活动家)和environmentalist(环境保护家)在谈论ecocatastrophe(生态危机)，设法解决airpollution（空气污染），nois