A rapid，accurate nuclear magnetic resonance( NMR) spectrometric technique was developed for the qualitative analysis of polyoxyethylene ether maromonomers in polycarboxylate superplasticizers. The main characteristic peaks in the NMR spectra of macromonomer were assigned，and the molecular weight was obtained by 1H NMR signal component analysis. The molecular weight was further verified by GPC. Meanwhile，esterification rate and residual rate of double bond were detected by 1H NMR in esterification reaction. The experimental results confirmed that NMR spectroscopy can be used to quantify the structures of macromonomer in polycarboxylate superplasticizers.