Cognitive impairment is a common non-motor symptom with higher disability in Parkinson’s disease(PD). The prediction and early identification of cognitive impairment in PD is one of the current challenges. Multiple types of biomarkers related to PD are under clinical evaluation,among which quantitative electroencephalogram(qEEG) is regarded as one of the biomarkers for evaluating cognitive impairment in PD. This article reviews the research progress in qEEG and cognitive impairment in PD.