The application of polyacrylic acid depended on the size of the molecular weight.The polyacrylic acid with low molecular weight,good water soluble and larger polarity,can combine to the polyvalent metal ion such as calcium and magnesium ions,and formation soluble anionic.Therefore,using polyacrylic acid with low molecular weight as water stabilizer had significant inhibition effect.The polymerization mechanism,synthesis methods and research status of the polyacrylic acid with low molecular weight were reviewed.In addition,the application prospect of polyacrylic acid was briefly introduced.