简介：Toenlargethemiddle-incomegroupandconstructthe'olivary'incomedistributionbecomesoneoftheimportantissuesoftheeconomicdevelopmentandincomedistributionreforminChina.Theincomedistributionfunctionisestimatedwithkerneldensity,andtheincomedistributionM-curveisconstructedwithCHNSandCHIPdatatocalculatethemiddle-incomegroup.Furthermore,acomparativeanalysisiscarriedoutforthechangingtrendofthesizeandproportionofmiddle-incomegroup.Researchconclusion:itisdiscoveredaccordingtotheincomedistributionM-curvethatthekeytotheenlargementofurbanmiddle-incomegroupliesinthelowermiddle-incomegroup,whilethekeytotheenlargementofruralmiddle-incomegroupliesintheimprovementoftheuppermiddle-incomegroup.Therangeofmiddle-incomegroupisexpanding,butduetothesmallscale,lowproportion,andpoorstability,ithasnotdevelopedthe'olivary'incomedistributionstructureyet,andincomeinequalitytendstobedeepened.