采用透射电镜研究了深冷处理对ＳＡＥ４８２０渗碳钢ＴＥＭ组织的影响。用Ｘ射线衍射法对表层残留奥氏体和残余应力作了定量分析。结果表明，深冷处理可促使残留奥氏体向马氏体转变，淬火马氏体回火后析出高度弥散的超微细碳化物，降低残余压应力。残留奥氏体由５０６％降为３４８％，切向／轴向残余压应力由２００６～２５９６ＭＰａ降为８２６～９４４ＭＰａ The effect of cryogenic treatment on TEM microstructure of SAE4820 carburized steel was studied by transmission electron microscope. The surface retained austenite and residual stress were quantitatively analyzed by X-ray diffraction. The results show that cryogenic treatment can promote the transformation of retained austenite to martensite. After quenching martensite tempering, highly dispersed ultrafine carbides are precipitated and the residual compressive stress is reduced. The residual austenite decreased from 506% to 348%, and the tangential / axial residual compressive stress decreased from 2006 ~ 2596MPa to 826 ~ 944MPa