The rapid development of intelligent substation makes the monitoring data of substation monitoring system constantly increase, and data anomalies occur frequently, which seriously affects the safe and stable operation of substation. Therefore, it is urgent to clean the monitoring data and improve the data quality. In view of this, the research status of data cleaning technology is summarized. Specifically, firstly, the substation monitoring system and its data problems are described. Then, the common data cleaning methods are summarized and compared from three aspects: correlation analysis, abnormal data detection and data repair. Finally, the problems encountered in the research are analyzed and the outlook is made.