The addition of high range water reducing admixture(HRWRA) is an important approach to prepare high performance cement mortar.The effect of high concentration type naphthalene series(superplasticizer(H-UNF)),common type naphthalene series(superplasticizer(C-)UNF) and polycarboxylate type superplasticizer(PC) on early-age cracking and volume stability of cement mortar was investigated by means of multi-channel ellipse ring shrinkage cracking test,free shrinkage and strength test.The general effect of UNF and PC is to increase initial cracking time of cement mortars,and decrease cracking sensitivity of cement mortars.As for decreasing cracking sensitivity of cement mortars,PC>H-UNF>C-UNF.To incorporate HRWRA apparently increases free shrinkage of cement mortars when keeping the constant m_w/m_b ratio and the content of cement pastes.As for the effect of controlling volume stability of cement mortars,PC>C-UNF>H-UNF.Maximum crack width of cement mortars with PC is lower,but the development rate of maximum crack width of cement mortars with H-UNF is faster in comparison with control cement mortars.Flexural and compressive strength of cement mortars at 28 d increase with increasing superplasticizer dosages under drying conditions.PC is superior to naphthalene series superplasticizer(UNF) in the aspect of strength increase.